Low stress training (LST) is a method used by cannabis growers when they want to increase their yield and take control over the shape and height of their plant. When it comes to training cannabis, there are low stress and high stress methods. Low stress training gently manipulates the cannabis plants, while high stress training involves more aggressive techniques that can ultimately cause stress to the plant.
Benefits of LST
LST brings many benefits including:
- Larger yields, even when using an identical setup as an untrained crop
- Total control over the height, shape and size of the plant
- Many different colas, or growth sites, are created instead of just one on each branch
High stress training vs low stress training cannabis
High stress training involves cutting the upper leaves off (known as “topping”) so that the light can penetrate the lower leaves. High stress training however, is just that – it can be quite stressful to the plant. That stress can cause several smaller branches to develop, leaving growers with small popcorn buds instead of the big colas they’re looking for. And in conditions of very high stress, it can even cause the plant to hermaphrodite.
LST cannabis on the other hand, is low stress, and if done properly, it shouldn’t bring any stress to the plant at all. LST isn’t invasive for the plant, and doesn’t involve cutting any portion of the plant.
Instead, growers simply bend the upper branches out and away from the center of the plant and tie them down in a more ideal position using wire or soft ties. This creates a more even surface, meaning all of the buds will be receiving approximately the same amount of light, instead of the top cola being the only one to get maximum light exposure, as it does in untrained plants.
But LST training is more than just getting increased light exposure to other areas of the plant. It actually causes a chemical reaction in the plant that gives growers more colas, which ultimately means more buds.
This is because, when a shoot from the plant is bent and tied down, it actually tricks the plant into thinking it just lost that shoot entirely. To make up for this, the plant will release chemicals that will grow more colas, or more growth sites, which can ultimately create more buds and give the grower a much bigger yield. And it will do it all without actually cutting the plant or stressing it out.
Some growers top their plants in addition to using low stress training, but it’s important to know that this is not true LST. To be truly and completely LST, the plant cannot be harmed or cut in any way.
Low stress training step by step
While training a plant can sound intimidating, especially to new growers, it’s very easily done in just a few steps.
- Grow a plant until it has three or four sets of leaves. Some growers choose to wait until
there are five sets, but it’s important to use caution. As the plant grows, the main stem will start to firm up and become more difficult to bend without breaking them. It’s important not to break the stem, as this can greatly stress and damage the plant, and if the main stem is broken, it could even kill the plant.
- Choose the tie that will be used. Some people choose hooks, using them to hook into the ground after a branch has been bent. Anything can be used, but it’s important that any ties directly touching the plant be soft so that they don’t cut into the branches or leaves of the plant. Pipe cleaners work very well, as they can be tied loosely and adjusted as the plant grows.
- Choose how the plant will be tied. Again, hooks can be used to secure into the ground, the plant can be tied down onto the pot, or it can be secured elsewhere.
- Tie the plant around the last internode – the area between the last set of leaves and the second-last set of leaves. Gently tie this area and secure to the spot that’s been chosen.
- The top of the plant that was just bent will start to bend back up towards the light. This could take as long as a whole day, but under very powerful lights it can take as little as three hours.
- Continue waiting. Tying should not be done until a new leaf set has formed. New branches will start forming at the sides of the plant, as more light is getting to the main stem.
- Once new leaf sets start forming, those can be tied down around (or into) the pot (as directed in step 4) until there is no longer room in or around the pot.
- By this point there should be enough new growth that the stem can be bent horizontally around the inside of the edge of the pot. Metal hooks or soft ties should be used. It’s at this time that more side branches should be coming in very nicely.
- Steps 7 and 8 can be repeated as growth continues, and side branches continue to form and reach up towards the light.
10. Wait for the plant to flower. This will be around the same time that it’s time to switch the plants over to a 12/12 light cycle so it can start creating the beautiful buds growers are looking for.
Some growers choose to turn the lights off two full days before harvest, and let no light touch the plants at all. This again tricks the plant, making it think it’s dying, which will cause it to release all of the resin (THC) in its system, placing it right onto the buds that have formed. At harvest time, these buds are going to be covered in beautiful crystal!
Is SCROG LST?
Another popular type of training is known as SCROG. This works very similarly to LST but uses a
screen to train the plant. The top of the plant is pulled through the screen so that the entire plant can actually be spread out, as well as allow for better light to reach the entire plant. Like LST, SCROG setups allow the grower to manipulate the plant to shape it and make better use of their space.
Typically in SCROG setups however, the top needs to be cut off and so, SCROG is not technically low stress training.
Auto-flowering cannabis LST
Unlike standard cannabis plants, which depend on light cycles to fully mature and produce buds, auto-flowering plants depend solely on age. While auto-flowering plants, like all plants, still need light in order to thrive, it does not change when they mature or when they start producing buds. Because of this, auto-flowering plants can reach full maturity within just two or three months.
This doesn’t mean that LST methods won’t work with auto-flowering plants, but it does mean that they should absolutely never be cut. Plants typically need some time to recover after such an invasive procedure, time that auto-flowering plants just don’t have.
Low stress training cannabis can be a great way to develop the flat, bushy plants that growers without a lot of space are looking for. And even more importantly, it’s a great way to get the massive yields that all growers want as an end result. While it can seem intimidating, it’s really a matter of just a few steps and once LST has been tried once, it only gets easier in subsequent grows.