Stages of the marijuana plant growth cycle

Cannabis plants, like all living things, go through a series of stages as they grow and mature. If you’re interested in cultivating cannabis, it’s especially important to understand the changes a plant undergoes during its life cycle, as each stage of growth requires different care.

Different stages call for different amounts of light, nutrients, and water. They also help us decide when to prune and train the plants. Determining a plant’s sex and overall health rely on stages of growth as well.

Generally speaking, it takes anywhere from 14-32 weeks, or about 4-8 months, to grow a weed plant.

The biggest variability in how long a marijuana plant takes to grow will happen in the vegetative cycle—if you’re growing indoors, you can force it to flower after only a few weeks when it is small, or after several weeks when it is big. If you’re growing outdoors, you’re at the whim of the seasons and will have to wait until fall to harvest. The plant will develop buds in the last 8-11 weeks.

The life cycle of cannabis can be broken down into four primary stages from seed to harvest:

  • Germination (5-10 days)
  • Seedling (2-3 weeks)
  • Vegetative (3-16 weeks)
  • Flowering (8-11 weeks)

Light cycle: 18 hours of light

(Elysse Feigenblatt/Leafly)

The first stage of life for a cannabis plant begins with the seed. At this point, your cannabis plant is dormant, patiently waiting for water to bring it to life.

You can observe the quality of the seed by its color and texture. The seed should feel hard and dry, and be light- to dark-brown in color. An undeveloped seed is generally squishy and green or white in color and likely won’t germinate.

To begin growing from a seed, learn more about germination here. This stage can take anywhere between 5-10 days.

Once your seed has popped, it’s ready to be placed in its growing medium. The tap root will drive down while the stem of the seedling will grow upward. Two rounded cotyledon leaves will grow out from the stem as the plant unfolds from the protective casing of the seed. These initial leaves are responsible for taking in sunlight needed for the plant to become healthy and stable.

As the roots develop, you will begin to see the first iconic fan leaves grow, at which point your cannabis plant can be considered a seedling.           

Light cycle: 18 hours of light

(Elysse Feigenblatt/Leafly)

When your plant becomes a seedling, you’ll notice it developing more of the traditional cannabis leaves. As a sprout, the seed will initially produce leaves with only one ridged blade. Once new growth develops, the leaves will develop more blades (1, 3, 5, 7, etc.). A mature cannabis plant will have between 5-7 blades per leaf, but some plants may have more.

Cannabis plants are considered seedlings until they begin to develop leaves with the full number of blades on new fan leaves. A healthy seedling should be a vibrant green color. Be very careful to not overwater the plant in its seedling stage—its roots are so small, it doesn’t need much water to thrive.

At this stage, the plant is vulnerable to disease and mold. Keep its environment clean and monitor excess moisture.

Light cycle: 18 hours of light

(Elysse Feigenblatt/Leafly)

The vegetative stage of cannabis is where the plant’s growth truly takes off. At this point, you’ve transplanted your plant into a larger pot, and the roots and foliage are developing rapidly. This is also the time to begin topping or training your plants.

Spacing between the nodes should represent the type of cannabis you are growing. Indica plants tend to be short and dense, while sativas grow lanky and more open in foliage.

Be mindful to increase your watering as the plant develops. When it’s young, your plant will need water close to the stalk, but as it grows the roots will also grow outward, so start watering further away from the stalk so the roots can stretch out and absorb water more efficiently.

Vegetative plants appreciate healthy soil with nutrients. Feed them with a higher level of nitrogen at this stage.

Light cycle: 12 hours of light

(Elysse Feigenblatt/Leafly)

The flowering stage is the final stage of growth for a cannabis plant. Flowering occurs naturally when the plant receives less than 12 hours of light a day as the summer days shorten, or as the indoor light cycle is shortened. It is in this stage that resinous buds develop and your hard work will be realized.

If you need to determine the sex of your plants (to discard the males), they will start showing their sex organs a couple weeks into the flowering stage. It’s imperative to separate the males so they don’t pollenate the flowering females.

There are a number of changes to consider once your plant goes from its vegetative stage to flowering:

  • Your plants shouldn’t be pruned after three weeks into the flowering stage, as it can upset the hormones of the plant.
  • Plants should be trellised so that buds will be supported as they develop.
  • Consider feeding plants with blooming nutrients.

What week of flowering do buds grow the most?

Buds typically grow the most toward the end of the flowering cycle, around week 6-7. You probably won’t notice much budding out at the beginning of flower, and it will slow down toward the end of the cycle, when buds become fully formed.

This post was originally published on July 18, 2017. It was most recently updated on January 17, 2020.

Once the buds have reached full maturation, it’s time to harvest.

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Bigger isn’t better: The case for growing small marijuana plants

We’re not going to delve into other matters where this might be up for debate, but when it comes to cannabis, bigger doesn’t mean better. Sure, giant weed plants look really cool. If nothing else, it’s ridiculously impressive that a warm season annual can go from seed to tree-sized in a matter of months. We get it.

But when it comes to the actual growing, drying, flavor, and quality of your crop, don’t be suckered into thinking that size is everything. In fact, we have solid reasons to encourage you to embrace smaller plants in your garden.

No matter the size, your neighbors might be able to smell the goods from over the fence. But you’ll keep your garden much less conspicuous by growing plants on the smaller side. While weed cultivation might be legal in your state, we’re still operating in a grey area due to federal illegality.

If someone’s got a vendetta against you, you’re just better off not having weed plants towering above fences and in plain sight. And besides revenge seekers, there are people who might be tempted to steal your crop if you’re making it too easy for them.

The best method of pest control always starts with you giving your plants a once over. That’s quite easy to do when plants are on the smaller side. You can reach up or kneel down, walk around your plant, and give every leaf and bud an inspection, usually without breaking a sweat or taking all day.

Things get a little more complicated when you need a ladder to do the same thing. Not only do you open the door to injury from falling, but it’ll take much more time when you’ve grown giant plants. You’ll likely skip the task entirely, opening the door for pest problems to get out of control.

Massive buds definitely look cool, but it can be a headache to try and dry them properly. A tasty, usable crop depends on buds drying evenly from the outside in and inside out. This is a much more reasonable task if buds are a manageable size. Once they feel dry from the outside, a few days of burping them in a storage vessel will suck out the remaining moisture.

Bigger buds are more difficult. Even when you think buds are dry on the outside, they might be packing quite a punch of moisture on the inside. Not only will curing be much more of an artform and take much longer, you’re much likelier to end up with mold problems.

If you’re not sold yet, this one will get you: The Emerald Cup judges often hand out awards to buds coming from plants that yield less than two pounds. Simply put, smaller plants can produce better tasting weed.

Think about it: A plant’s goal in life is to reproduce. If it’s stressed in any way, it abandons unnecessary tasks (like packing on extra foliage) and focuses everything on reproduction. That’s why you hear so much about mouthwatering dry-farmed tomatoes or grapes. The harvest might be smaller, both in fruit size and yield, but the taste is unbeatable, as stressed out plants pour everything they’ve got into their fruit, flowers, or seeds.

In the case of weed, that means stickier buds loaded with terpenes and packed with cannabinoids. Don’t take our word for it—Happy Dreams Farm, Eel River Farms, and High Water Farm are just a few of the Humboldt-area spots having great success with dry-farmed weed. Their plants are itty bitty and tasty as hell.

Not shooting for massive weed also bodes well for the environment as well as your pocketbook. You can skip the heavy doses of fertilizers in the false thinking that bigger weed yields tastier plants. What you want to do is a lot simpler and a lot less expensive.

When you first plant your weed outdoors, make sure the soil is amended with plenty of quality, finished compost. Truth be told, that’s likely all your weed needs for the growing season. It’ll be just enough to get the plant growing nicely, and not too much nourishment for the plant to get lazy about flavor.

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Is a cannabis cultivar the same as a strain?

As a longtime gardener, I was so delighted by cannabis the first time I included it in my garden. It’s unlike anything I’ve ever grown—it’s the only dioecious plant that needs me to sort males from females, its smells are fantastic and pungent, and its stickiness is so unique (and sort of annoying).

But there are a few other, less fortunate things, that make it unlike other crops, including some inaccurate terminology used by growers and consumers alike. While we’re finally starting to accept that indica and sativa are unreliable labels for categorizing plants, my biggest beef is with the use of the term “strain,” when what is really meant is “cultivar.”

Many cannabis enthusiasts are eager for normalization of the plant they love so much, and I believe that using accurate lingo to talk about the plant would go a long way in that effort.

“Cultivar” is short for “cultivated variety.” This is a horticultural category (as opposed to a taxonomic one) to describe a plant that’s been selected and improved upon by humans. It can be a hybrid (either intentional or not), or selected from the wild, brought under cultivation, and distinct enough to warrant a naming. No matter the origin, it’s something that’s been touched by the human hand through selection.

In writing, cultivars always appear in single quotes, non-italicized, following the genus and species, like this:

  • Cercis canadensis ‘Forest Pansy’
  • Rosmarinus officinalis ‘Tuscan Blue’
  • Festuca glauca ‘Elijah Blue’

The International Cultivation Registry Authority is responsible for the registration of all cultivars. The system is voluntary, focused on making sure cultivar names are distinct. It should be noted that cultivar registration is unrelated to Intellectual Property rights. Those sorts of legal rights must be sought through plant protection programs, patents, and trademarks, which are an entirely different ballgame.

It should be noted: offspring of cultivars are all genetically identical replicas, reproduced by cloning or vegetative cuts. For a cultivar to come from seed, a breeder needs to go through several generations of backcrossing for a reliably stable offspring.

Strain is the term most often used in microbiology and virology. It refers to a genetic variant or subtype within a microorganism. Think: flu strain.

The term is not often used to describe plants. It does sometimes show up in breeding, but mostly as it relates to genetic modification. If genes of a wheat plant are altered, the offspring of that modified plant might be deemed a strain.

Subspecies

Like genus and species, subspecies is a taxonomic rank, just below species. Subspecies are geographically isolated from other members of the species in a habitat. Although it’s genetically possible for the subspecies to interbreed with other members of the species, it doesn’t happen in nature due to the isolation. Because of that sequestration, subspecies can take on different characteristics from other members of the same species.

Some examples include:

  • Euphorbia characias ssp. characias (Mediterranean spurge frond from Portugal to Crete)
  • Euphorbia characias ssp. wulfenii (Mediterranean spurge found from Southern France to Anatolia)

Variety

Just like genus or species, variety is a taxonomic rank, more specific yet than subspecies. A variety is a form of a plant that’s different from the rest of the species in habitat. Think: a usually purple-flowered vine that also produces some rogue flowers in white.

Here’s the real rub with varieties: Gardeners have a tendency to use the terms “cultivar” and “variety” interchangeably. I’m super-duper guilty of this one. But they’re not the same. Unlike cultivars, varieties aren’t the results of human-initiated breeding. They’re 100% found in nature.

Some examples include:

  • Acer palmatum var. atropupureum (Purple Japanese maple)
  • Cercis canadensis var. alba (While flowering redbud)

Landrace

Not a taxonomic rank, this refers to domesticated, locally adapted populations. They’re impacted by both human selection as well as the natural environment. While a landrace population might look relatively uniform, we can generally think of them as rich genetic reservoirs, full of the building blocks for modern breeding programs.

They’re also, more and more, a thing of the past. We think of landrace populations as being largely pastoral in nature, maintained in rural regions by more traditional farming practices.

What we call “strains” should absolutely be called “cultivars.” These are cultivated varieties, hybridized and bred by humans. The clones you buy are genetic replicas of their parent, and any seeds you buy should hopefully have been properly stabilized and come true to their namesake.

Where it gets a little tricky is that there is no accountability or oversite of cannabis cultivar names. So, one clone or seed of “OG Kush” might come true to the parent, but it also might be totally different from someone else’s “OG Kush.”

What we call “landrace” is permissible when we talk about populations that were grown in isolation. A few examples that come to mind are Lamb’s Bread from Jamaica and Hindu Kush from the Middle East.

As for “indica” and “sativa”—it’s really time to let these go. Some people believe them to be historical subspecies of the plant, having evolved in different parts of the world, but given that these populations were always under human cultivation, I find “landrace” a much better term for regional populations.

Perhaps we can think of wild, uncultivated populations, like ruderalis, as a subspecies. But indica and sativa? They are all but outdated terms, used in recent times to describe feelings of the high rather than descriptors of the plant and its origins, but even then, they are inaccurate.

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Does cloning ruin cannabis strains over time?

If you’re a cannabis enthusiast or familiar with the basic principles of botany, you’ll know that cannabis plants come from two sources: seeds and clones. One of the enduring debates among cannabis growers is the merits of growing from seeds versus cultivating from clones.

Seeds are created by sexual propagation and contain genes from both parents, rendering the seed—and the plant the seed grows into—genetically unique.

Cannabis clones are cuttings taken from a healthy female—called a mother plant—that has been grown from seed or is itself a clone. So cuttings can be taken from clones, or clones of clones, ad infinitum.

After a cutting of a growing branch is taken, it’s ideally dipped in a hormone medium and then roots out. Through this form of asexual reproduction, identical cannabis plants can be grown abundantly and for free for successive generations. Or can they?

Cannabis cloning represents an incontestably straightforward way of getting identical cannabis. What’s more, it’s currently the most dominant method of cultivating cannabis. In a commercial context where consumers demand consistency, it’s a gift.

However, there are murmurs among seasoned growers that clones lose potency over time. Some think it’s the phenomenon of clonal degradation: the notion that cannabis clones drift away from the mother plant’s genes over subsequent generations, resulting in weaker plants that yield less and become more susceptible to pests and fungi.

Clonal degradation, or genetic drift as it is sometimes called (though this term is debatable), is fiercely contested in the world of weed: some maintain it is a myth, while others insist it’s a real phenomenon. Cannabis chat rooms are saturated with arguments over how clonal decay occurs, with some blaming mutation in clones, while others point to cellular degradation when they become “cloned out.”

Let’s unpack genetic drift by briefly revisiting some of the basics of high school bio.

Cloned cuttings can’t change their genetic imprint because a clone is an exact genetic replica of the mother plant. A clone is even the same cellular age as the mother plant—a one-week-old clone taken from a two-month-old mother is actually two months old.

Genetic variation comes from sexual reproduction, i.e., with seeds. While genetic mutations can occur as a result of growth, it doesn’t mean that the gene pool of cannabis clones dramatically changes from generation to generation.

But the same clones subjected to different environments often look and grow differently. An under-fertilized clone in a low-humidity environment will grow with less vigor than its sister receiving perfect fertilization and humidity in a grow room across town. Environment plays a critical role in the growth and health of a cannabis clone.

The field of epigenetics offers valuable insights for understanding how cannabis clones can appear to lose potency. Epigenetics refers to outside stimuli, or modifications, that can turn genes on or off. It’s not that there is an alteration of the genetic code in the clone; rather, environmental factors modify its genetic potential and expression.

“Epigenetic impacts on clone health over time are very significant. Without proper mineral nutrition and biological health, the vigor of a clone will diminish over time as it continually is replicated, thus reducing its viability,” said Russell Pace III, President of the Cannabis Horticultural Association.

Epigenetics provides us with a more nuanced understanding of the nature versus nurture paradox. Genes load the gun, as the saying goes, but the environment pulls the trigger.

So now that we know successive generations of cannabis clones aren’t genetically inferior in some way, what are some of the environmental factors or stressors that affect the growth of clones?

Environmental elements that are essential to optimizing clone potency include the maintenance of appropriate levels of light, humidity, soil nutrients, and water. Stressors that should be avoided include over or underwatering, over or underfeeding, incorrect soil pH, and inconsistency with light cycles during the vegetative and flowering cycles. Pesticides can be another stressor that can damage plants when misapplied or applied overzealously.

Taproots: they’re important

Another inevitable contributor to clonal decay that isn’t environmental may be the lack of a taproot. Cannabis grown from seed has a taproot—a central root which is sent deep into the soil from which subsidiary roots grow.

When a cutting is taken from a cannabis plant, the cutting must develop a tangle of roots to funnel up moisture and nutrients. Clones lack a taproot and therefore are structurally (not genetically) distinct to cannabis grown from seed.

“The lack of a taproot definitely affects the vigor of a cloned plant when compared to the growth rate of a seed plant,” said Pace. “A seed plant will be infinitely more robust and have faster growth rates in most cases.”

Cleanliness is critical to clone success

The mere act of taking a cutting from the mother plant also introduces a host of potential problems. Aside from inflicting transplant shock on the clone, the cut part creates an easy passage for pathogens such as bacteria, viruses, and fungi to weave their way in, causing infection.

“Basically, a clone infected with a virus is like a dud where it grows slow and really doesn’t produce very well,” said Pace.

Growers who scrupulously sterilize cloning equipment and use proper techniques will have greater success cloning without issue. When every care is taken to ensure that the cutting is taken as gently as possible, and appropriate rooting and hormone mediums are used, the clone is more likely to extend a robust rooting system and grow strong and healthy.

That said, however, cannabis horticulturist Jorge Cervantes points out that genetic mutations can and do occur in clone populations as they grow and can be passed on through cuttings. While peer-reviewed studies exploring the intricacies of cannabis botany are still few and far between, there is research to suggest that phenotypic variation—that’s variation in physical characteristics—in plant cuttings is due to sporadic mutations in the DNA sequences.

A theory known as Muller’s ratchet argues that clone populations are doomed to accumulate increasing numbers of harmful mutations, which inhibit the plant’s ability to grow and thrive. Some interpret it as nature’s way of showing a preference for sexual reproduction in plant populations.

What’s more, telomeres may also play a role in clonal decay. Telomeres are protective caps at the ends of chromosomes that ensure DNA is copied accurately when it divides. When telomeres are stressed or damaged, the very end of the DNA strand doesn’t make it into the new copy, which results in a loss of vital genetic information.

It can be helpful to conceptualize this process like a photocopier cutting off the last line of text from a page each time it is copied—analogously, DNA strands may become shorter with every cell division.

The result is that plants lose their competence to undergo normal cell division, and healthy growth becomes decelerated or arrested. While we still don’t know a lot about how telomeres work in cloned plants, or more specifically in cloned cannabis plants, we do know that telomere shortening can be exacerbated by environmental stressors and physiological processes such as aging.

And it’s important to only clone from mother plants in a vegetative state as this study shows that age may play a role in clonal genetic mutations. Older mothers that have already been through flowering cycles are not an optimal source for cuttings because the stress of these processes compromises their genetic integrity.

Ultimately, there is a host of factors that may contribute to clonal decay. While the control of some elements is out of our hands, clonal degradation can be somewhat avoided with proper care, technique, and management of clones. Take clones from robust young mothers using sterile equipment, provide them with the best possible environment, and there’s no reason they won’t thrive for generations.

What’s most promising, according to Pace, is that even damaged or weak clones can be nursed back to health with the right growing conditions such as healthy soil.

“I think this is a most promising type of immunotherapy, so to speak,” says Pace. “Healthy soil biology can act as epigenetic gene therapy for plants. The grower attempts to create optimal environments loaded with beneficial biology and a well balanced soil chemistry.”

This epigenetic gene therapy, of sorts, can boost the innate immune systems of clones. “It essentially allows them to express their highest level of epigenetic potential. It’s really fascinating and something I’ve witnessed first-hand,” said Pace.

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How to regulate temperature and humidity in your indoor marijuana grow

Cannabis, like all plants, prefers certain environmental conditions in order to thrive. One of the major benefits of cultivating it indoors is that growers have the ability to manipulate their environments to suit the needs of the plants. Temperature, humidity, light intensity, and airflow are all factors that will need to be monitored and regulated in order to keep cannabis healthy through its different phases.

Cannabis is a resilient plant that can survive under a range of conditions. However, for the most part, it prefers to be kept under the following conditions in each growth stage for optimal health:

  • Seedlings/clones: 75-85°F (with lights on), ~70% relative humidity
  • Vegetative growth: 70-85°F, ~ 40-60% relative humidity
  • Flowering: 65-80°F, ~40-50% relative humidity

To understanding how to regulate your indoor environment, equip yourself with these cheap and easy-to-use tools to take measurements. You’ll need:

  • Thermometer: A basic one will allow you to measure how warm or cool the environment is inside your garden.
  • Hygrometer: This measures humidity, or more specifically, water vapor content in the air.
  • Infrared thermometer, or IR thermometer (optional): IR thermometers use a detection device called a thermopile to measure surface temperatures. Although not necessary, these are helpful in finding out leaf temperatures, which will give you an extra layer of knowledge on how to properly regulate environmental conditions.

Now that you have the tools to take correct environmental measurements, you can begin to make actual changes. The two factors you need to control to dial in the environment are temperature and humidity.

Inevitably, there will be fluctuations of these two in your garden. These fluctuations can occur both throughout a grow space as well as within pockets inside a given room. They can also occur at different points within a given day or throughout a season as conditions change in the environment outside your grow space.

Regulating Temperature

This can be achieved by manipulating four factors.

Light. The largest impact on the temperature in your garden is the type of light you use and how much heat it generates. Different grow lights will give off different heat signatures and depending on the size of your indoor space, room temperature can vary. Hot lights such as metal halides (MH), high-intensity discharges (HIDs), and compact fluorescent lamps (CFLs) will produce much more heat in a small space than LEDs. However, even LEDs produce some heat.

Additionally, lights can be raised or lowered to change temperature at the canopy level.

Airflow. Controlling airflow is the best way to move hot and cool air throughout your grow space. Airflow can remove warm air produced from lights out of the garden and bring fresh cool air into it when needed. Airflow can also help exchange air throughout your canopy, cooling leaves in the process.

Fans and ducts help regulate airflow—fans push air where it is needed and ducting can direct air into and out of your grow space, as well as to specific areas.

Inline fans pull cool air from outside of the garden inside, stationary and oscillating fans push fresh air throughout the garden, and ducted hoods can remove hot air produced by lights away from the canopy.

Air conditioners. In order to rapidly cool a grow environment that is too warm when light and airflow manipulation aren’t doing enough, you may need to bring in an air conditioner to cool the overall temperature of your grow space.

Heaters. Some gardens may actually require warm air, especially during times when lights are off and not generating heat. This is where a heater can come into play.

Regulating Humidity

Humidity is the measure of water vapor in the air. There are four things you can use to help control it.

  • Dehumidifiers: Dehumidifiers remove moisture from the air. These units are used much more frequently in indoor grow spaces because plants in a confined space tend to create moisture, and the space will usually feel warm and humid.
  • Humidifiers: A humidifier can produce a constant flow of water vapor for an indoor garden. They use cool water to create a mist that disperses throughout the space and increases moisture levels.
  • Airflow: As with regulating temperature, regulating airflow will allow you to move moisture in and out of your grow space and control humidity. Simply opening up a grow space, i.e., opening the door to your grow room or tent, can bring down the humidity level.
  • Water: In the absence of a humidifier, you can mist plants with a spray bottle to create extra moisture.

Balancing the system

It can be a tricky getting the right balance of temperature and humidity because they affect each other—turning up your dehumidifier will lower the humidity of your grow space, but it will also increase the temperature of the area. This in turn may require you to turn on an AC unit—everything’s connected!

Depending on how severe the seasons are in your area, you can schedule your light cycles depending on the temperature outside—in the summer, the heat outside your grow and the heat inside generated by the lights might be too much for your plants, so you may have to turn the lights on at night when it’s cooler outside. The same is true for winter—you may have to shift the light cycle to nighttime so that your plants don’t get too cold.

For growers who have a little extra money to spend and want full control over their indoor garden, environmental controllers will allow you to automate the process. These devices are essential for monitoring and controlling your environment if you’re away from your garden for any amount of time.

Controllers monitor conditions within your garden and are connected to devices necessary to manipulate those conditions. You can connect a controller to fans, dehumidifiers, humidifiers, heaters, or air conditioners, and set thresholds whereby each device will power on and off based on your ideal environmental settings. Some units run autonomously, making changes based on set parameters, while others allow you to control each element via an app on a phone, tablet, or computer.

Your average homegrower doesn’t necessarily need to know this method for regulating your environment, but if you want to get really scientific about it, here goes.

Once you familiarize yourself with how to use a thermometer, hygrometer, and IR thermometer, you can go a step further and learn how to extrapolate data from them to properly correct environmental conditions in your garden. You can do this by understanding the Vapor pressure deficit (VPD) of your garden.

VPD is the best metric for measuring and mitigating indoor grow conditions because it provides a stable unit of measurement among the constant shifts in a garden’s temperature and humidity.

Plants primarily absorb water in order to stay cool. The majority of that water comes in through the roots and out the leaves through tiny pores—called stomata—in a process called transpiration.

Inside of a healthy leaf, relative humidity is around 100%—this means that gasses within the leaf are 100% saturated with moisture, creating pressure (saturated vapor pressure, to be exact).

The stomata on a leaf’s surface act as valves for moisture, transpiring vapor quicker when hot and dry, and slower when humid. Plants like to have their stomata open so that photosynthesis can occur. When proper conditions within the plant are not met, plants can close their stomata in an effort to keep water in, thereby halting photosynthesis.

To measure VPD, you need these readings:

  • Air temperature
  • Humidity
  • Leaf temperature

Without an IR thermometer, you can still get a leaf temperature estimate by taking a temperature reading at the canopy level with a standard thermometer.

There are plenty of VPD calculators and charts available online that can help you figure out this metric for your garden. You will simply need to input the three metrics above into the calculator or use a chart to get an estimate.

Cannabis requires the following VPD in these phases to thrive:

  • Propagation and early veg: 0.4 – 0.8 kPa
  • Late veg and early flower: 0.8 – 1.2 kPa
  • Mid-flower to late flower: 1.2 – 1.6 kPa

Using VPD to measure your garden conditions will allow you to easily make environmental changes based on where your conditions sit on the chart. Making environmental changes based on temperature or humidity alone won’t necessarily look at the whole picture of plant health as using VPD does, even though it may be more complicated to determine.

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How to choose a cannabis cultivar for your homegrow

Growing

November 19, 2019

(Artem Cherednik/iStock)

Because of 100ish years of prohibition, limited record-keeping, and a lack of well-quantified data, any list of cultivars claiming they are best for this, that, or the other, is totally subjective. How then is one supposed to choose from the many hundreds of cultivars of weed out there when looking to start growing yourself?

While we refuse to drum up our own list of specific cultivars, we instead offer some guidance to help you choose for yourself.

We know what you’re thinking–if you live somewhere hot with long summers, plant a sativa, as those evolved closer to equatorial climates. And if you live anywhere with a shorter growing season, reach for an indica, as those hail from harsher northern climates.

Here’s the thing–widespread hybridization means that there’s really no such thing as an indica or sativa anymore. What you get is going to be a hybrid, period.

What you will no doubt be presented with in any cultivar description is what it will do to you. Proceed with caution: Because of everyone’s individual brain and body chemistry, these descriptions don’t necessarily apply to everyone. One person’s couch lock is another person’s dance party. Truthfully, depending on the set and setting, your couch lock on one day might be your dance party on another.

We say: Go for it. Especially if you’re going to grow your own, you’re going to be smelling a lot of this plant. Why not have it be equal parts gardening and aromatherapy?

Cultivars often give a hint of smell in their name, indicating if they’re on the fruitier side (Mango, Blueberry, Orange Cookies), skunkier side (Island Sweet Skunk), earthier side (Earth OG), or gassy side (Sour Diesel). Not only may these terpenes impact your high, they most certainly surround you as your plants grow.

Again: Go for it. Let’s face it–a lot of weed looks similar once it’s dried. Why not have a little fun with color in the garden? Certain cultivars turn intensely purple, especially as cooler fall temperatures approach. Others have brightly-colored pistils–a real delight when flowering starts.

How to find cultivars with colors? Look for clues in their names. Anything with purple (Granddaddy Purple) or blue (Blue Dream) in its name likely has some color during the growing season.

Given that so much of cannabis cultivation is a gamble and everything’s a hybrid, we totally condone choosing based on name–it’s sort of like choosing a wine bottle based on the label. Why not?

Maybe you want Green Crack or Purple Monkey Balls growing in your garden, and that’s OK. It’s also fine if you stick to something friendlier sounding, like Cherry Pie or Mango Tango.

Acapulco Gold? Pineapple Express? White Widow? All classics. Go for it. But it’s important to understand that at this moment in time, there’s no accountability or regulation when it comes to genetics and names. OG Kush sold from two different vendors might have vastly different DNA.

It’s also important to understand that seeds with the exact same DNA will still produce distinct plants with their own unique expression of cannabinoids and terpenes. Terroir–a.k.a. soil and climate–impact how a plant grows and what chemical compounds eventually pack its flowers. Environment plays a huge role in a plant’s ultimate expression.

If you can connect with a local community of outdoor cannabis growers, they’ll be your best bet for telling you what cultivars do well in your particular climate. It’s highly likely that they’ll have a few extra seeds to share too. Over time, plants grown in a specific climate and allowed to produce seeds will adapt better and better to that particular locale.

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How 4 growers bring out unique traits in their cannabis plants

Growing

October 30, 2019

The diversity of cannabis genetics is increasing with every new phenotype that pops up. As legal markets with data and analytics illustrate what consumers are buying, a sea change is brewing in what traits cultivators are seeking in their plants.

Yield, potency, and hardiness used to be primary concerns, but craft cultivation now is pristine flower and more–it’s about hyper-fragrant nose notes, intense flavor expressions on the palette, rare terpenes and cannabinoids, and in some cases, practical reasons like easier harvesting or soil stewardship.

Leafly asked four cannabis producers to discuss breeding insights and find out exactly what they are looking for in plants.

Pete Pietrangeli, product development manager with Indus Holdings, founder of Acme Premium Vapes, and LA Confidential dispensary, is involved with all steps of the business, from genetics to vape production.

Based in Salinas, California, his grow runs on a combination of sun and power, but it’s too large to function as an indoor operation. Live resin, terp sauces, and boutique extracts are their thing, and those have to come from perfect flower.

That means lots of crossbreeding to find the best traits. “This is what has led many growers to breeding their own seeds with special traits that can endure various climates. For example, crossing white widow into popular strains was widely used in the Hawaiian islands, to combat mold and mildew which White Widow is very resilient to,” says Pietrangeli.

Flavor can often be temporary in cannabis products, hitting the nose but not the mouth in the smoke or vapor. Their Lemon Cake live resin is one of the rarest expressions they’ve ever been able to achieve. “It is definitely rich in limonene, however, it has a different smooth finish that doesn’t just give you a taste and ends abruptly but lingers on in your taste buds,” he says.

Cyril Guthridge of Waterdog Herb Farm in California’s Mendocino County doesn’t just grow cannabis on his lush piece of mountainside. As a working herb farm in addition to a cannabis grow, the symbiosis of dozens of plant species and animals is at play–and they influence their cannabis as well.

“We like to plant high-terpene plants near our cannabis and feed our [cannabis] other terpene-rich plants. We have seen great results from our trials and experiments with this,” says Guthridge.

With plants like qinghao, a.k.a. wormwood, and lavender brushing stalks with the huge, sun grown crop, Guthridge’s land is producing some really unique cannabis flower.

“This year we have a few very special terpenes we are excited about. One is from a ‘Galicot’ from StaeFli Farms,” he says. “It smells like fresh mint cookies with a drizzle of skunky garlic sauce.”

Waterdog Farms has no trouble getting big buds, but they’re all about results, not quantity. “I will always choose to grow a unique cultivar over a large yield any day,” says Guthridge. “I’m not interested in growing the biggest plant. I want to explore the nuances of the genetics within the profiles it has and help express those qualities through our cultivating techniques.”

CEO and founder of Endo Industries, Nancy Do, has a unique approach to coaxing the best out of her plants. Endo designs and produces healthy cannabis clones in Northern California, and they are thinking a few steps ahead to help farmers get there too.

“We do spend a lot of our time at the moment just creating and engineering pathogen- and disease-free plants for growers, which is such a huge feat in itself,” says Do. But she is the first to admit how vast the future of cannabis genetics is looking, especially when looking past the high-THC breeding rush of the past 10 years and into the other compounds in cannabis.

“Aside from terpenes, we’re definitely looking into flavonoids, and other secondary metabolites. It’s not just that there’s medicinal purposes and that they express these amazing things in the plant that we enjoy consuming, it’s also that it helps the plant become stronger and more vigorous,” says Do.

Cannaflavins are big on Do’s list of exceptional traits to look for, as a set of flavonoids exclusive to cannabis could have anti-inflammatory properties. And there’s still more research to come that can be applied to cannabis genetics.

As people depend more and more on cannabis for medicine, preserving it is a goal for Do and her company. “Ultimately, we have to think about heat tolerance and heat resistance, as well as drought tolerance, because global warming is accelerating. Farmers across the board have to think about this, breeders have to think about this,” says Do.

This is scary stuff, but Do thinks it’s time to be realistic. “What was viable in their climate now or even five years ago will be different in five more years at the rate we are going,” she says.

Pieter Summs, lead grower at Oregon’s Otis Gardens, runs an indoor operation that’s up-to-date with cannabis’ evolving requirements. Part of this involves introducing physical traits to a genetics program, which Summs says, “Allow for easy workability of the product, such as a high calyx-to-leaf ratio for easy trim-ability of the flowers and easy maintenance of the live plant.” These adjustments make the plant do well in close quarters as well as make harvesting more simple.

As for the unique flavors and scents, Summs shouts out their own strain, Dethman Ridge Skunk. “Her off-fruity smell evolves from around week six, a room of Dethman is undeniable from yards outside. Rock hard flowers offer a slightly savory smell the further into flower she progresses,” he says.

No matter what a cannabis producer is coaxing out of their creations, it all adds up to a better product in your pocket. We’re only just now seeing the landscape reveal itself from the fog of prohibition, so there are decades of genetics experiments to come, and most importantly, to learn from.

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4 cannabis producers on what makes a strain great to grow

Growing

October 1, 2019

(Julia Sumpter)

It can be hard enough to decide what strain to purchase or grow yourself, so can you imagine the pressure of doing so for a large scale cannabis operation?For the uninitiated, strains are not one-size-grows-all by any stretch of the imagination. Cultivators who produce flower for your local dispensary need to put a lot of deliberation into the process. Tossing dead plants when things go awry is something a big commercial grow simply cannot afford to do.

Temperature, humidity, pests, light availability, and lots of other factors can trash a grow, and commercial farmers have to know every detail while still providing big yields. It’s a lot more than just making a basic cannabis bonsai like the rest of us beginners.

We spoke with four growers about which strains get the job done of getting you high. Getting an inside peek into how some of today’s powerhouse cannabis companies pick their genetics for efficiency and fragrance is valuable advice for hobby growers, consumers, and anyone else with a passing interest in the plant.

Strain selection can often come down to climate and terroir, especially with sun grown operations. Aster Farms, a popular Lake County, California, cultivator, has a high elevation coupled with less humidity: In terms of weed, the low moisture atmosphere can help cannabis thrive in cold nights, with lower chances of mold and frost, which are certain weed killers.

Aster Farms’ CEO Julia Jacobson says this lets them aim for tropical sativas that typically don’t perform well in California weather, and that the terpene content is heavily influenced by the operation’s live soil techniques, which create fungal networks that some growers swear by.

“Since our climate is higher and drier, we are able to grow less hardy and longer-taking varietals–sativas and more tropical strains like White Widow. Therefore, we have the advantage of being able to select strains based on our product portfolio and desired effects, not having to worry about climate,” she says.

Founder and CEO of Paradiso Gardens Christina Dipaci had genetics optimized just for her setup. Their Salinas Valley, California, grow calls Grandiflora Genetics’ Project 4516 one of their most popular strains.

“Grandiflora’s strains are all bred to yield well and be resistant to bugs. Working with the breeder helps us develop the perfect environment for each particular strain,” says Dipaci.

Paradiso often does trial periods to analyze key strains before completing full runs, which allowed them to determine that Project 4516 was a prolific choice. Dipaci explains, “Project 4516 is ideal for the customer and the op because we are able to grow it to its fullest expression of color, taste, and flavor at a larger scale.”

You can find Nug California products at dozens of locations around the Golden State, and their size would probably allow for national distribution if federal law were remotely at that point.

Until then, despite having their favorite cultivars racked up to rake in the big buds, master grower Ryan Tonsberg cites Strawberry Fruity Pebbles, Sunshine OG, and Kush Mint Animal Cookies as their standout strains. These were the finalists of over 40 choices, Tonsberg explains, and they test four new strains per month, constantly fine-tuning their selection.

He said the Sunshine OG and Strawberry Fruity Pebbles thrive because “Their genetics match our environment really well. We have large grow rooms so it’s not possible to dial in temp and humidity for each strain individually. We have to run on what’s ideal for most of the stains we carry.”

He continued: “If a strain is really susceptible to pests or disease, we have to take that into consideration. Production and ease of cultivation are important, but our guys are willing to put in the extra time and effort if the strain is worth it.”

Johnny Casali, chief cultivator at Huckleberry Hill Farms–who supplies to California mega-brand Flow Kana–cultivates his mother’s 45-year-old strain, Whitethorn Rose, for its supreme quality.

“Bred from a strain that has been cultivated on the same exact property for the last 45 years, I truly believe that it is adapted to the special terroir and thrives here better than anywhere else in the world,” Casali says.

Heritage strains like Whitethorn Rose even cost Casali time in prison, but this did not deter his stewardship of it into today’s place of esteem.

Terpenes are every plant’s natural pest repellent–the main reason you rarely see spider mites and aphids on culinary herbs. Casali says this is a boon in cannabis language as well, “One of my favorite parts of cultivating Whitethorn Rose is that because of its high terpene profile, it’s super resistant to any kind of pests and any kind of molds including powdery mildew. For me, this is a huge advantage.”

With the legal market primarily based in the West Coast for the time being, there’s no telling what people will be crossing to make potent and pest-repelling piff in the coming decades–likely in new locales where cannabis was once illegal.

For now, these entrepreneurial cultivators are building the lasting foundation of the commercial cannabis industry, and it says a lot about what will be on shelves in the years to come.

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How to Set Up a Small-Space Drying Room for Your Cannabis Harvest

When it comes to having a usable, smokable, great-tasting crop, it turns out that growing cannabis is really only half the journey. After harvest, a proper dry and cure are crucial. These steps help retain terpenes and cannabinoids while diminishing chlorophyll, giving you something that tastes more like grass than, well, grass. Not to mention, the right conditions in a grow room prevent mold, so post-processing is an important time to pay careful attention.

No matter the size of your grow setup, a few truths remain: You should dry your weed in a dark room with temperatures between 60-70?F and humidity between 50-65%. A cheap hygrometer will take the mystery out of monitoring those numbers.

And the good news is that, in a small space, simple oscillating fans and small humidifiers or dehumidifiers (depending on your climate) should be plenty to nudge those numbers in the right direction should they be off by a few. Also, any spot you choose should be tidied up and mold-free.

If you’re in a small home or apartment or simply don’t want the dry and cure to take up too much room, here are some space-saving tips to help you minimize the footprint of the last phase of the growing journey.

Hang Branches Efficiently

Hanging harvested plants upside down is the gold standard for drying practices. It prevents buds from getting flattened or misshapen as they dry. Also, keeping flowers connected to branches for as long as possible helps create an even, slow dry–exactly what you’re after.

To make hanging even more efficient, forgo hanging branches directly on a line and instead place them on a hanger. Many more hangers can fit on the line than just branches alone. BAM–you’ve just exponentially increased your drying space. It’s a-OK for branches to be close together, but leave a little room to encourage airflow and prevent mold.

Minimize Building New Structures

For a neat and tidy hanging apparatus that takes no construction and requires no drilling into walls, purchase a freestanding wardrobe from any department store, online retailer, or thrift store.

They’re available in all sorts of sizes and come ready-made for hangers with nothing more than the twist of a few screws. They’re super sturdy, too, able to support the weight of freshly harvested branches–something that you should account for in your setup.

Trim Off Extra Leaves

Greatly reduce the volume of plant material by manicuring your cannabis before you hang it to dry. Getting rid of all those fan and sugar leaves results in much slender branches, which take up a lot less space.

Opt for Flat Racks

(A flat rack for drying buds. Courtesy of Rachel Weill)

Or skip the branches altogether and just dry the buds. Trim wet and put all buds on a hanging herb-drying rack, sometimes called a “high-rise drying rack.” They are circular with layers of mesh lining (great for airflow), and can be lined with flowers.

This will let you dry just the part you’re ultimately after, skipping any excess material like sticks and stems. Racks come in varying sizes and heights, going up to eight levels tall.

There are a few things to keep in mind should you go this route. First, weed should be trimmed and bucked–snipped off its main stem and into smaller nugs–to make maximum use of space. This means the dry will happen more quickly, so be sure to check on your flowers often. You’ll want to get them into jars to cure at the right time, rather than having them dry to a crisp.

Drying flat also means the buds will get a little smooshed on one side, the side on the rack. This is purely an aesthetic concern, but one to be aware of should impressing your friends with perfectly shaped weed be your end goal.

Skip Transferring Buds Before the Cure

When branches snap and buds sound like popcorn when pressed gently, the bud is considered to be mostly dried, and it’s time for the next step: curing.

During curing, moisture continues to draw from the center of the bud toward the outside. Most people consider their cannabis to be cured after two weeks to a month. For reasons that relate more to tradition than actual need, people take all sorts of secondary steps to cure their weed after it’s dry. For example, they transfer almost-dried branches to paper bags, cardboard boxes, or plastic bins.

All of these involve a transfer, another setup, and most importantly, more room. Skip it. When your weed is dry, buck it off stems and trim it if you haven’t already, and place it directly into your curing vessels–mason jars or locking stainless-steel tubs both work great.

Seal them overnight and check on them the next day. If the flowers seem to have regained their moisture, leave the lid off all day before resealing at night. Repeat this process–known as burping–until you find them as dry as you left them the night before. Judge this by giving them a gentle squeeze.

If you’re unsure, you can also procure a digital moisture meter, available for $20 or so at any hardware store. You’ll stick the pins into the bud and a moisture reading pops up on the display. The ideal moisture for fully dried and cured cannabis is a steady 10-15%. Voila, your cure is done, and you haven’t had to acquire any more vessels or take up any more room to make it happen.

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Get Beautiful Buds With These Outdoor Cannabis Harvesting Tips

For those of us growing cannabis outdoors, we get to reap the benefits of gardening in the natural world. We skip the artificial light, ubiquitous chemicals, and noisy inline fans, and instead use sunlight, living soil, and gentle breezes to nurture our plants to maturity.

Of course, the great outdoors has its downsides too, like unpredictable weather, pests, and nosy neighbors. Following these tips will help ensure a smooth outdoor harvesting process, just as Mother Nature intended it to be.

Know When to Pull Your Harvest

All cannabis, no matter the variety, is a warm-season annual, meaning it grows and matures in one season. How long of a season a variety needs depends on where its ancestors evolved.

Those from regions close to the equator–sativa types–need a long, seemingly endless summer to ripen fully. While those from harsh, colder climates–indica types–tend to finish earlier since, well, winter is coming.

Having said that, rampant hybridization means nearly any variety you’ve got growing in your yard has a mix of both indica and sativa in its DNA. Expect them to ripen sometime between September and October in the northern hemisphere.

Keep a careful eye on pistils–the hairs that stick out from the flowers. When half of them are still upright and the other are half darkened and curled, your crop is ready for harvest.

Mind the Weather

With cannabis ripening as the seasons change from summer to fall, chances are high that the weather is going through some changes. Depending on your climate, there might be cold snaps or rainstorms on the horizon.

Does this spell disaster? No way. But it does require paying attention and possibly making game-time decisions on the right time to chop, always balancing peak ripeness with conditions that could compromise your harvest.

Cold

Most cannabis plants can sail through a light freeze (28 to 32?F for up to three hours) with no trouble. A hard freeze, on the other hand–any lower temps or longer hours–will most likely spell disaster. Frost damage causes ice crystals to form within plant tissue, damaging their cells.

Leaves appear wilted before turning dark and crispy. The deeper the frost, the more of the plant that will get damaged.

Note that potted plants experience more severe temperature fluctuations than plants in the ground, making them more susceptible to frost damage.

If there’s some indica buried in a plant’s genetics, purple coloring might become much more pronounced once it gets some cold under its belt. And again, because of hybridization, don’t worry if you think you’ve got a sativa in your garden–it can likely handle a brief cold snap with no problem.

Rain

Similar to a cold snap, it’s not the rain itself that’s a huge problem, it’s the duration and severity of the storm. If it’s going to warm up and dry out quickly, you can feel fully confident in leaving not-quite-ripe cannabis to weather the storm. If the rain will be there to stay, problems with mold await. Cut your losses and harvest before things get soggy.

Note that in cold or rain–especially rain that might become hail–you can create a buffer by surrounding your plants with a few tall stakes and draping burlap or a tarp over the top. Just be certain to remove the cover when the cold/rain passes to let the plants warm up and get the sun and air they need.

Choose Your Harvest Pacing

With artificial light and complicated pruning practices, most indoor weed ripens all at once. There can be a little more variation in plants grown outside, with outer, exposed colas ripening first, and interior, more shaded buds ripening a few days later.

Generally speaking, you’re fine harvesting all at once. But you also have the option of dividing the work, harvesting ripe ones first and leaving inner ones to soak up the sun and ripen fully for a little longer.

Get Your Systems in Place

You’ve hopefully set up a drying room–you know, the cool dark space with a temperature that stays between 60-70?F, and humidity that remains between 50-65%.

But not so fast–how are you getting there? Use fresh tarps or rinsed out (and dried!) bins to keep your harvest clean on its path from outdoors to inside. Have different tarps or bins for each variety, and make sure each is labeled. Also make certain you’re ready for trimming with clean bypass pruners.

Go Time

Make a go of it when temperatures are cool, like first thing in the morning or right before the sun sets. Intense light and high heat degrades THC.

Pest Patrol

Freshly cut branches offer an easy opportunity for a close-up inspection. After chopping, hold each branch up to the light and give it a once-over. If you see anything fishy–deadened, brown, or grey areas of flower or leaves–cut them out fully and clean your shears with rubbing alcohol before making any other cuts. Any problems with fungus or mold can spread rampantly in the drying room.

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Is Vertical Growing the Future of Cannabis?

Indoor cannabis grows are expensive operations. Given the real estate costs, massive energy bills, and significant staffing requirements, it’s crucial to find a way to increase profits. Maximizing your grow space is one way to do this and that could mean vertical growing–the practice of producing plants in vertically stacked layers or vertically inclined surfaces.

In the food sector, vertical growing companies like Plenty, Aerofarms, Gotham Greens, and many more, are revolutionizing agriculture. But in the cannabis industry, which practically invented sunless growing, there has been notably less activity.

This is partly because high-pressure sodium lights (HPS), one of the most common lights used to grow cannabis for decades, run so hot that plants have to be many feet away to stay unharmed.

But LEDs run at much lower temperatures, so you can install them inches from the plant canopy. Their decreasing price and increasing ability to equal or exceed HPS yields are making LEDs the standard, finally opening the door to vertical growing for cannabis.

“The main catalyst behind cannabis cultivation going vertical is the improved performance of LED lighting,” says Thomas Rogers, LED engineer of Exact Lux. “Cannabis growers are approaching us wanting the most powerful multi-tier or ‘vertical farm’ lighting systems possible.”

Two Types of Vertical Farming

Stacked vertical (left) and true vertical (right) cannabis grows with LEDs. (Sean Walling/Leafly)

Stacked Vertical

The most common method of vertical farming is a stacked vertical setup–levels of plant racks with LED lights above each rack. Plants are topped and defoliated to keep them short and bud-heavy.

Growers even stack in the flower stage, despite plants being large and top-heavy.

True Vertical

With true vertical growing, plants grow out the side of a column, and water and nutrients drip down from the top–see these examples from ZipGrow and Tower Garden.

Within the column, a hybrid method combines nutrient film technique (NFT), where nutrient water is passed directly over the roots, and aeroponics, a soilless grow method where roots hang in the air.

Pros and Cons of Vertical Growing

So why don’t all cannabis operations grow vertically, especially in this competitive new industry? Here we’ll look at some of the benefits and drawbacks.

Environmental Conditions Get Complex

Maintaining optimum temperature, humidity, and air circulation is tough for all cannabis grows. But in vertical growing there is even more variability in macro and micro environmental conditions because there are more plants, making control more difficult.

Because of this atmospheric variability, Hugh Gaasch, engineer at STEM Cultivation, recommends sensors to detect data points like moisture changes. “Shockingly, the majority of commercial growers I’ve seen to date use a single temperature/humidity sensor to monitor a room, even large spaces, over 20,000 feet.”

In contrast, STEM Cultivation uses one temperature sensor per 100 cubic feet. STEM collects data on: temperature, humidity, air pressure, CO2 levels, lighting levels, lighting power (kW) and energy (kWh), system air circulation rates, localized air circulation, VOC (volatile organic compounds), and HVAC power and energy, to name a few.

Mike Zartarian, from Zartarian Engineering, builds circulation systems for vegetable and cannabis growers. To decrease chances of mold and fungi, he says: “I recommend systems that push air right in between the racks above the plants, usually with small ducts that take air from the edges of the room to the center of the racks.”

Expensive to Set Up and Maintain

Although vertical growing of any kind will increase yield by maximizing space, when you add up the increased energy usage from more artificial lighting, an upgraded climate control system, the extra infrastructure required (ladders, racks, sensors, and more), and paying high-skilled agro-technicians, it is very costly for many.

Zartarian says: “It’s by no means impossible, but the jury is very much out on whether it’s cost effective long-term. If veggie growers prove it to be a dominant technique, I would expect to see more experimentation on the cannabis side.”

As it is, licensed operators he works with are struggling to meet demand and prefer to stick to more traditional techniques they know will produce.

Dangerous Conditions

Vertically grown cannabis needs a lot of hands-on attention during the flowering cycle as compared to, say, vertical lettuce crops which are more set-and-forget. The height of a plant must be closely controlled, which requires grow technicians to get up on step stools or scaffolding to reach into the plant canopy. These high-tier tasks may not be OSHA-compliant.

Certain Cultivars Work Better Than Others

The most successful cultivars for vertical growing are short, have big buds, and fewer leaves, so less defoliation is necessary. But if you’re a confident defoliator, the diversity of cultivars you can grow will broaden.

Arthur Brownsey, cannabis cultivation consultant at Four Trees, thinks most strains can grow vertically. “If you have a tight production schedule, group like-cultivars together, and plan accordingly, there are no restrictions to what you can grow.”

Agro-engineer Aja Atwood of Trella sees value in vertical growing, but the limited cultivars it serves made her determined to find another option. “There is a wide variety of strains out there that prefer longer vegetation periods and have a taller growth structure. In order to diversify, you need to train or trellis those taller varieties to stay within the space.”

To allow for vertical growing with a diversity of strains, she and her partner Andres Chamorro invented a grow unit, TrellaGro LST, that trains plants to grow horizontally. Each unit is vertically stackable and equipped with LED lights that follow it as it grows sideways, allowing for taller strains and less energy use.

Stay Tuned

In these early days, vertical growing has yet to revolutionize the industry, and some operations, focused on supplying a high-demand market, are sticking with traditional growing methods.

However, most operations already know the price of cannabis will likely drop as competition grows. In that climate, the future of cannabis could move up, not out.

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Opinion: Why Growing With Hydroponics Is Better Than Soil

There’s a lot of wariness around hydroponic growing, particularly for homegrowers looking to establish small-scale grows. But although it may be more expensive to get started with than soil, hydroponics can be a superior way of growing cannabis, and hydro technology is getting cheaper and more accessible every day, offering a range of benefits over classic soil-based cultivation.

Here we’ll take a look at its primary advantage, an increased level of control, as well as three secondary advantages: efficiency, versatility, and sustainability.

Getting Started

A basic hydroponic setup–deep water culture (Amy Phung/Leafly)

Patience is crucial with hydroponic growing. Despite all its advantages, it’s often more labor-intensive and has a higher skill barrier.

With a soil grow, your primary concerns will center around light and nutrients; with hydroponics, you still have to be deliberate in those areas, while also managing a complex and sensitive system that circulates water and nutrients among your plants.

It’s essential that you have a strong command of your system, as the health of your plants depends on it. Hydroponic cultivation is much less forgiving of small mistakes than growing in soil.

Since nutrients are delivered directly to your plants’ root systems, you’ll need to ensure you’re delivering an optimal mix, as over-fertilizing can have disastrous results. The complexity and sensitivity of hydroponics systems also means they’re an investment of time and money.

You can design and set up a relatively low-cost setup, but it requires a strong understanding of the basic principles of hydroponic cultivation. Alternately, you can forgo designing your own setup and buy premade solutions. A system capable of growing 5-6 plants can start at around $100, and quickly increase from there with features that increase control and ease of use.

Of course, once you’re set up and have a couple of grow cycles under your belt, the costs will level off, and the increased yield and quality will quickly make up your initial investment.

If you are jumping into hydroponics, just make sure to continue your research and look carefully before you leap.

Control Your Environment

A hydroponic grow allows you to exercise total control over the quality and quantity of nutrients your plants receive, whereas with soil grows, nutrients remain in the soil. The nutritional needs of cannabis plants vary throughout the grow process and with hydroponics, you’re able to dial in the mixture of nutrients and tailor it specifically to their progress.

It is worth keeping in mind, hydroponics may require a higher degree of care than a soil grow. Microorganisms in soil can help restore balance in case of issues like a pH imbalance or over-fertilization, but since hydroponic mediums don’t have this capability, you’ll need to be careful and deliberate in the ways you nurture your plants.

Closely monitoring your water’s pH and overall quality, selecting and measuring your nutrients with extreme care, and maintaining a consistent temperature are key to a productive hydroponic grow.

However, this degree of sensitivity also allows you to make small adjustments to maximize yields, which is more difficult in a conventional soil grow. You’re also be able to directly examine your plants’ root systems in a hydro grow, ensuring your plants are developing in a healthy way.

Save Time and Space

The increased level of control offered by hydroponics allows you to grow your plants more efficiently. By creating the ideal circumstances for plant growth, you’re able to maximize the productivity of each plant.

An indoor hydroponic grow allows your plants to mature faster and more evenly. Year-round hydroponic systems can yield multiple harvests annually, though strain genetics also play a role in that as well.

Since you’re going to be delivering nutrients directly to each plant, each plant’s root system requires significantly less space than with a soil grow. Less space needed for roots means you can use a grow space more effectively, whether it’s a walk-in closet or a warehouse. The only factor that will limit your number of plants and the density of your canopy is the strength and availability of light.

You’ll also be able to use less nutrients overall, as they are absorbed directly into the plants, with nothing lost in soil.

Grow Hydroponically Indoor or Outdoor

The classic image of hydroponic cultivation is large, intricate, expensive systems in industrial warehouse grows, but hydroponic cultivation is actually much more accessible than that.

If you’re a homegrower with the right equipment and expertise, you can set up a hydroponic grow in a space the size of a walk-in closet and yield far more than you would with a soil grow in a comparable space.

Hydroponics can be scaled to any grow size or type, and will confer the same advantages no matter how large or small your grow.

Most hydroponic systems are used to grow indoors. However, as long as you have a reliable power supply, hydroponics can be used to grow outdoors, particularly in greenhouses. While you’ll have to deal with factors like light, temperature, and humidity, growing hydroponically in a greenhouse will allow you to maximize yield and quality while avoiding the massive energy requirements of indoor cultivation.

Sustainability

Sustainability is an oft-overlooked benefit of hydroponic cultivation. With soil cultivation, a significant portion of the water you use never gets to your plant’s roots. With hydroponics, you’re able to precisely deliver the exact amount of water each plant needs, without wasting any.

Also, many of the insect and disease problems faced in the cannabis cultivation process are the result of soilborne infestations. Since hydroponics dispenses with soil, the reduced risk of pests means your need for pesticides will be minimized.

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