How to Train Cannabis Plants for Maximum Yield
Updated on April 12, 2022
" Simple! It all comes down to a few key elements..."
1. It Increases Yield
2. More Cannabinoids
3. Less Grow Space
4. It Decreases Pests
Did you know that...
Over 95% of legal commercial growers train their plants? Not only do they spend money buying training equipment, they also spend a lot of paid labour making sure their plants are well trained. This is a large investment, meaning they must be making that money back.
No more waiting. Let’s get right into it!
Need training supplies? Go ahead and grab yours now!
Maximize your yields in just 7 steps...
1st Step: pruning the 1st node
When: after 6th node appears
Cannabis seedling with 2 grown nodes, and a 3rd node coming out
2nd Step: topping for the 1st time
When: at the same time as Step 1
Topping above the 5th node and leaving 4 nodes/8 shoots behind
3rd Step: low-stress training
When: after shoots grow 4" to 6"
Training the 8 grown branches, and lightly defoliating
Low-stress training only with the BudClips
Low-stress training with the BudClips, BudPots, and BudHuggers
4th Step: topping for the 2nd time
When: new branches on 3rd node
Topping for the 2nd time, lightly defoliating, & re-training branches
When two shoots are asymmetrical, prune the smaller one
5th Step: flipping to flower
When: 1 week after last topping
This purple khush CBD is ready to flower
6th Step: mid-flower defoliation
When: after week 3 of flower
Defoliating after the third week of flower (stretch phase)
7th Step: late-flower defoliation
When: 1 week before harvest
Flowering plants that were defoliated 1 week before harvest
And you are done!
After the last defoliation is complete, wait about 1 week and you are good to harvest!
But wait... what about the science?
"The truth might surprise you... plant training doesn’t actually increase yields..."
What plant training does is that it increases the rate of photosynthesis in your plants, which is a process that combines CO2 from the air and water from the ground with energy from the sun, and transforms them into oxygen and sugars.
The oxygen from this process goes back into the air (for us to breathe - thanks plants!), but the sugars stay in the plant and work together with other nutrients in order to grow roots, stems, leaves, and flowers (AKA bud!).
Pro Tip: the more photosynthesis, the more bud!
And for more photosynthesis, you need The 3 Pillars of Plant Training...
Ready to train your plants with the most durable products in the market?
The 3 pillars of cannabis plant training
Here are the 3 most effective ways to increase your yields with plant training.
1. Light Exposure
2. Air Exchange
3. Hormonal Distribution
Let's look at how each of these elements contribute to photosynthesis, and how to set up your plants for optimal growth.
1. Light Exposure
Imagine two plants: one is tall and skinny, and the other is short and wide. When you look at both from the top, which one will have more “leaf space” to collect light?
Tall & skinny vs short & wide plant
As we can see from the diagram above, the trained plant has a much larger surface area when looked at from the top, meaning it is collecting nearly twice as much light as the untrained plant. A good comparison is that training a cannabis plant for light exposure is the same as spreading out solar panels (i.e. your plant's leaves) that were previously stacked on top of each other, so that the bottom panels can catch some light. Here are the two most common ways to accomplish more light exposure.
Low-Stress Training & High-Stress Training
Low-Stress Training, or LST (on the left) vs High-Stress Training, or HST (on the right)
The first way to gain more light exposure is called low-stress training (LST) and it involves gently bending the branches of your cannabis plant sideways and then tying them with a garden tie.
The second way to increase light exposure is called high-stress training (HST), which involves bending the branches of your cannabis plants until they "crack" into position, thus removing the need to tie them down.
While both techniques achieve the same result for light exposure, we don’t recommend HST since it stresses the plant by up to 3 days, while LST only stresses the plant by just a few hours. In fact, HST is used more often as a remedy for when plants are growing too close to the lights and you can't tie them down anymore, while LST is used much more broadly.
If you want to find out more about Low-Stress Training, read this complete LST guide.
2. Air Exchange
Did you know that 99% of the water your plants absorb via their roots evaporates back into the air via tiny little holes under their leaves called stomata? Seriously, your plants are like humidifiers, and the reason for this is that the more they transpire, the more nutrients make their way up with that water and stay inside of the plant. Water works mostly as a nutrient carrier for your plants, as 99% evaporates in the air.
But something else happens while plants transpire and water evaporates. Since the stomata are open, the leaves take this opportunity to absorb CO2 and expunge oxygen at the same time, thus enabling the photosynthesis process. In a nutshell, the more your plants transpire, the more nutrients they take up via the roots, the more CO2 comes in via the leaves, and the more they photosynthesize (and grow).
So, if you want to maximize your transpiration and CO2 intake you need to increase the airflow around your leaves so that they can exchange the outgoing air with oxygen + high humidity with incoming air with CO2 + low humidity.
To accomplish this, you can do one of two things: you can always use low-stress training in order to “spread-out” the branches and create more air space inside the canopy, or you can also defoliate and prune the old leaves and growth sites that are blocking airflow to the middle of the plant.
In fact, when leaves become clustered they inhibit airflow and also attract many pests. This is why it is important to remove leaves and branches from your cannabis plant in a way that contributes to more air movement. But be careful! Defoliation and pruning can be damaging too. Read this article to learn how to prune & defoliate cannabis plants for maximum yield.
3. Hormonal Distribution
The reason why a lot of plants grow toward the sun in a Christmas-tree shape is because they produce high levels of growth hormones (called auxins) nearest the top of the plant, while inhibiting the side branches from getting it. This phenomena is called apical dominance, and is the reason why cannabis grows one tall cola in the center and many smaller ones off to the side. This plant, for example, grew “naturally”. You can see how much thicker the top cola is compared to the side ones. This is not good because it means you get some good bud from the very top but a lot of popcorn bud from everywhere else.
Untrained plant (on the left) vs Trained plant (on the right). The colas are much thicker on the trained plant.
How the hormones work
Generally, indoor growers want their plants to grow as much cannabis as possible, but they also want to use as little space as possible. Training marijuana plants allows you to control their final shape, meaning that you can make them as short or as wide as you want in order to fit whatever space you have to work with.
There are two main ways to better distribute auxins throughout the plant. We can apply LST or HST to bend the top of the main stem horizontally, such that the side branches become level and start growing stronger. The second way is called topping (ta-da!), and over 90% of legal commercial growers do it in order to improve their yields. Topping involves cutting the growing tip of a cannabis plant so that all the auxins that were being produced there can now start being produced on the side branches instead.
The effect of auxins on plants
Another way to shift hormones in the cannabis plant is by pruning weak shoots (AKA growth sites AKA new branches) so that they don’t develop into weak colas during the flowering stage. When you remove the weak branches, you give the larger branches an opportunity to grow even stronger (as we learned on Step 4 of our cannabis training method).
Putting it all together
The truth is that there isn’t a single technique or method that works best. What does work best is putting all of these 3 elements - light exposure, air exchange, and hormonal distribution - together in a way that maximizes the rate of photosynthesis of your plants. For this, we recommend doing a little bit of everything depending on your growing space.
Is that all there is to plant training?
" Yes! Here are other reasons why you should train your cannabis plants. "
We just saw that airflow is really important for transpiration and CO2 exchange, but we didn’t talk about airflow as a tool for pest prevention. Powdery mildew, which is a very common mold in cannabis, thrives in environments with humid and damp air. This is why you will usually find powdery mildew on the inner leaves of your plant before the outer ones - because they are more humid and have less airflow. Because of this, it is crucial to clear out the inner leaves of your plant (they are usually small, anyways).
Cannabis leaf with powdery mildew
Spider mites, on the other hand, are tiny bugs that eat cannabis leaves and make webs all over the plant, also like the same type of humid environment and will thrive if the temperatures are high as well. So if you can add some air movement by defoliating your canopy and using training techniques to “open up” your plant, you will make it very uncomfortable for pests to set in, which means they will end up choosing your neighbour's plants instead.
Home growers want their plants to grow as much cannabis as possible, but they also want to use as little space as possible. Training marijuana plants allows you to control their final shape, meaning that you can make them as short or as wide as you want in order to fit whatever space you have to work with.
With proper training you also don't waste your precious light on the floor of your tent or closet - instead you force your plants to occupy the entire grow space and collect all of the light available to them. In fact, a trained weed plant will almost always give you more grams per watt of electricity because you maximize your leaf area.
8 trained cannabis plants inside a 4" by 4" tent
When you prune the weak branches off of your cannabis plants and train the stronger branches to grow into a wider canopy, you are basically allowing your cannabis plant to focus all of its energies on the remaining, stronger growth sites. This allows these sites to grow even bigger, promoting much higher trichome concentrations at the tops.
When you don't train your plant, the energy it produces is distributed equally to every branch, weak or strong, and you end up with some bud that is good and some that is bad. It is much better to take control and only grow the good ones.
Cannabis flower from a trained cannabis plant
Learn to Grow Like The Pros
Time to get some things cleared up...
Frequently Asked Question #1
What is the difference between indoor and outdoor training?
Below are the 3 key differences between training cannabis plants indoors vs outdoors.
1. Light Source
Our sun is almost 100 million miles away from earth, so even if you have an outdoor plant that is 20ft tall, the bottom leaves and the top leaves will feel no difference in light intensity (as long as they are not shaded). However, when it comes to indoor lights the intensity of the light decreases drastically as you get farther away from the source - getting up to 5 times weaker every foot of distance.
What this means is that training cannabis indoors is essential for optimizing light distribution, like for example keeping a flat canopy and defoliating the bottom of the plant (like the plant on the right of this diagram). When growing outdoors, however, you don’t need to worry so much about this - just make sure to choose a spot in your backyard that has the most amount of sunlight, all day long. Cannabis does not like the shade!
High-intensity vs low-intensity zones for indoor lighting
As we have seen before, airflow is essential for plants to absorb CO2. For this reason, it is equally important to train indoor and outdoor plants to maximize airflow around the leaves.
The main difference, however, is that outdoors plants have the extra pressure from pests while indoor plants generally don’t. This is why we highly recommend defoliating outdoor plants at least once a month to clear out all old leaves that are turning yellow, not catching any more light, or that are blocking airflow to the middle of the plant. As long as you don’t create pockets of clustered leaves, you should be safe from pests.
Defoliating outdoors to prevent pests
When growing cannabis indoors, we never have to worry about strong winds breaking our stems. But outdoor growing is a different story. We personally have friends who lost entire plants because of strong winds that broke them at the stem. This is not an uncommon story.
Many growers fail to train their outdoors plants and instead let them grow naturally into the Christmas tree shape. The problem with this is that, after flowering, the untrained plant gets very heavy at the top, and any strong wind can break its main stem in half.
This is why it is crucial to give your outdoor plants the side support they need in order to survive strong winds. You can do this with tomato wires, garden stakes, garden ties, trellis nets, and ropes.
Outdoors cannabis plants with garden stakes and trellis nets
Frequently Asked Question #2
What is the difference between training indicas and sativas?
Below are the 5 key differences between training indica cannabis plants vs sativa cannabis plants.
Indicas vs sativas: the different shapes
- Easier to train
- Requires more defoliation and pruning
- Only needs to be topped once
- Needs to be trained less frequently
- Lower profile plants
Due to their genetic makeup, cannabis indicas have a sturdy growth structure, with thick fingered fan leaves and short spaces between each set of leaves (called internodal spacing). These features make indicas great for beginners who want to practice all training techniques, including topping, low-stress training, pruning, & defoliation. Since indicas are short and stocky, they are super easy to train when compared to their tall and lanky sisters: the sativas.
- More difficult to train
- Requires less defoliation and pruning
- Needs to be topped multiple times
- Needs to be trained more frequently
- Higher profile plants
Sativa cannabis strains have a tall and skinny structure, with longer internodal spacing (space between each node). This makes it extra important to constantly low-stress train and top them so that they stay low to the ground. We recommend topping sativas once every 2 weeks until it is time to switch them to flower. This will ensure your plants don't grow too tall too quickly and end up reaching your lights (indoors) or becoming prone to breaking under strong winds (outdoors).
Frequently Asked Question #3
What is the best way to train autoflowers?
Training auto-flowers is definitely not the same as photoperiodic plants. Here is why.
Two autoflowers that were low-stress trained and will be ready to harvest in 1 week
Autoflowers only have around 30 days in the veg stage before they automatically go into the flowering stage (AKA “auto-flower”), so it is best to only use low-stress training techniques on your auto-flowering plants and never top them! Here is a complete guide on how to low-stress train cannabis plants for maximum yield.
You should also avoid high-stress training or pruning, as they will also cause too much stress on your autoflowers and stunt their growth for a few days. Since autoflowers have such a short cycle, a few days is too much to afford and you will lose a lot of potential growth (and bud). In a nutshell: only LST your autoflowers, never top them, and only remove old and yellow leaves or very small shoots in the middle of the canopy.
Don't be afraid!
It is very common for new growers to fear training their cannabis plants. After all, you are hurting them by doing things that seem very counterintuitive. The thing is, if you get unlucky and break a branch that you can't tape back together, your plant will automatically start growing out the other branches and you won't lose much yield. All in all, it’s better to try and screw it up a few times while learning, because plant-training will be with you forever!