Low Stress Training (LST) Autoflowers – When and how?

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Autoflowers are incredibly versatile to grow However, the one downside is they yield much less than photoperiod strains. Using methods such as low stress training when growing autoflowers could be the answer to your problems.

Learn how low stress training autoflowers could increase yields and when and how to apply this technique to your grow without damaging your plants.

What does it mean to LST an autoflower?

Low stress training, commonly abbreviated to LST is a plant training technique whereby you manipulate the growth pattern to optimize light absorption and space.

The aim of LST is to gently bend the branches of your cannabis plant as it grows causing very little stress to it. To keep them in shape you tie them down, clip them or use a mesh/screen to fix their positions. By doing so you can encourage the plant to develop a wider structure with a flat canopy that allows the plant to absorb more light and produce multiple bud sites once it reaches the flowering stage.

Manipulating Apical dominance

If left untrained a typical cannabis plant will grow with an apical dominance. This means that the central stem of the plant is more dominant than the side stems. Naturally more energy is fed to this main stem forcing it to grow upwards towards the light. While this is a great feature to have in the wild when competing against other plants for the suns energy, it doesn’t necessarily help us when we are growing indoors with a controlled light source and nobody to compete against. So how do we fix this? We learn to manipulate the plants apical dominance.

Apical dominance is triggered in plants by the main bud producing auxin. Auxin is a plant hormone that encourages the main stem to elongate and grow upwards towards its light source to improve photosynthesis.

By bending a plants main stem and the others around it, auxin production is cut short forcing the plants energy to be spread among the other stems. This encourages lateral growth, allows you to control the height of a plant and create that desirable ‘flat canopy’ more easily.

What does LST do for autoflowers?

  • Limit growth hormone auxin which is responsible to creating a plants apical dominance.
  • By tying down the branches as it grows, the structure is manipulated.
  • Lateral growth is encouraged creating a flatter canopy.
  • Allows you to control height of a plant more easily.
  • Encourages a plant to produce more bud sites. 

defoliating autoflower cannabis plants

RELATED ARTICLE – Is It Okay To Defoliate Autoflowers?

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Is LST good for autoflowers?

Low stress training autoflowers will certainly increase yield, however, it does come with its drawbacks and risks that you should be aware of. Here are a few things to keep an eye out for when you begin to LST your autos.

Drawbacks of using LST with autos

  • Could cause damage – LST training increases the risk of damaging a plant. If it is not done carefully and using the correct methods you could damage the plant and cause stress. In the worst cases this can cause stunted growth.
  • Stunted growth – If you stress a photoperiod plant you can keep it in the vegetative stage for as long as you want until you feel that it has fully recovered. If this happens with an autoflower you do not have this luxury and any stress could mean your plant enters the flowering stage in a stressed state. This will impact both the yield and quality of the bud.
  • Increased risk of bud rot (if not careful) – LST training increase light absorption which boosts yields and plant density. This can reduce airflow and so you may need to use more fans and keep a closer eye on issues such as bud rot occurring.

Don’t let this put you off using LST training with your autoflowers. Stressing your plants is rare providing you are gentle with them when undertaking the low stress training and keep an eye on them as they grow.

Here are a few of the positives of why we think every grower, beginner or expert should be trying low stress training to grow their autoflowers:

Positives of using LST with autos

  • Optimizes light exposure – This allows the plant to photosynthesize more effectively. This increases bud size and yield.
  • Use space more efficiently – By manipulating the plants apical dominance you force the plant to grow with a wider flatter canopy which is ideal if you don’t have a tall tent.
  • Denser Buds – Not only does LST increase overall yield, the improved ability for the plant to photosynthesize also makes buds dense.
  • Low Stress / Big Yields – Its sort of in the name, but because you are slowly bending the branches as the plant grows LST if done correctly causes no stress or damage. Yet the results are huge and some growers report a 50-75% increase in yield.

Does low stress training increase yield? 

Yes. Done correctly low stress training autoflowers will undoubtedly increase yield. However, performing LST on autoflowers does take a little bit more time and attention as growers will be required to carefully bend the branches of a plant every few days using clips, cable ties or string. 

The aim of LST is to encourage lateral growth, this naturally will take up more space per plant. Therefore you should take into consideration how many plants you are going to grow in your tent or grow space before you begin. 

The yield of your grow is also dictated by lots of other variables so LST or any training method should not be used without also providing good lighting, soil, nutrients and pest control.

Should I use LST to grow autoflowers?

Low stress training is an excellent method for cultivators of any experience level to try. First off it is recommended that you get the very basics of plant care right, but LST is by no means complicated and can be carried out by anyone, providing you have the time and space.

LST is the perfect method for a home grower, cultivating with 1-4 plants in a small tent that has time to monitor and adjust the plants as they grow. Growing a small number of plants will allow you to optimise the tent and use up the grow space available. By doing this you can maximise the yield you get from each plant making those seeds as cost effective as possible.

Other growers that prefer something less time intensive or grow with much larger numbers of seeds, may prefer using methods such as SOG (sea of green) where there is less work to do. Of course LST can be done on a large scale but it will require more work.

How many plants per square meter with LST?

The number of plants you get per square meter is dependant on a few variables such as; Pot size, tent size, strain genetics, number and power of lights. 

However generally with your average LST autoflower grow you should be able to fit 2-4 plants per square metre while fully optimising the grow space.

Can you LST any autoflowering strain?

Yes, LST can work with any strain, however there will be some cultivars that work better than others. Sativa dominant autos tend to grow taller and reach up to 150cm, so there is more of a need to use LST to tie them down, limit height and encourage lateral growth.

That being said, it will also work with indica cultivars, although because of their naturally shorter, wider structure, you won’t see as much of an increase in yield.

Low stress training was created for strains such as Amnesia Haze and Tangerine Dream Auto. You can comfortably grow 2-4 tall autoflowers like this in a square metre tent and fully utilise the space to make the most out of each plant.

When should I start low stress training autoflowers? 

It is difficult to give an exact timescale on when to start low stress training autoflowers because it depends upon the rate at which your plants are growing. Ideally you should begin low stress training your autos when they have produced their first true set of leaves.

This is usually around weeks 3-4 of growth at which point the plant is normally 4-6 inches tall. A simple way to decide when to start LST with your autoflowers is to bend the branches gently by hand and check if they are able to reach the edges of the pot, if they can then it should be fine to start low stress training them.

When to stop LST on autoflowers? 

You should stop low stress training autoflowers once the plant has stopped growing. Some strains take longer than others, sativas normally take a little longer than indicas. In general most autoflowers stop vertical growth between weeks 6-8 so you should stop LST when you notice this. Once you stop the plant will begin to focus more of its energy on bud production and your hard work will pay dividends once it begins to fully bloom.

Can you keep your plants tied down up until flowering?

With LST you should keep your plants tied down in position right the way through to harvest. You only stop the process of bending the branches once the plant reaches the flowering stage. Leave any branches tied in position but don’t make any more bends or adjustments and allow the plant focus all of its energy on producing bud.

How to LST Autoflowers

There are three main methods of LST training, bending and tying, SCROG and SOG. Below is a step by step approach to each variation.

The bending and tying approach

This is the most straightforward and easiest way to LST train your autoflowers and involves using clips, darden ties or string to hold the branches in place.

bending and tieing lst training autoflower
  1. Once you have identified that the branches of your autoflower are able to bend down to the edges of the pot and it has produced its first true set of leaves, your plant is ready to begin LST. 
  2. With this method you need to first create some anchor points to fix your ties to. The most basic way of doing this is to drill a few holes around the edges of your pot in line with where the branches will bend down to and feed the ties through the holes and then around the branches.
  3. Make sure you are very gentle with the branches when you do this, remember this method is ‘LOW STRESS’ so make sure you do not cause any damage to the plant.
  4. The aim is to gently bend and tie the top branches down so that they are all level, this will create your flat even canopy.
  5. As your plant produces new branches tie these down too so that all of your branches are reasonably level and the plant is growing out horizontally.
  6. You do not necessarily have to use this method to create a flat canopy. You can also use it to bend and shape your plants however you want. To get the best results you should properly utilise the space available in your grow tent by bending a plant more towards areas of space or light.

The Screen of Green (SCROG) approach

The SCROG method is very straight forward, but it requires some DIY or prior setting up to do. It requires you to use a mesh, net or some kind of screen to encourage the plant to stay at the same height as it grows by bending them down and weaving them through it. Again this method helps to create that flat canopy effect that encourages bud production and increases yields.

screen of green training autoflowers
  1. First you will need a net or will need to make one. You can normally pick a small one of these up in a gardening store or on amazon for less than $10. You will also need a square frame to attach the net to. This is when growing in a tent comes in handy as you can attach the netting to the frame of the tent.
  2. Wait until the plants have developed at least 5 nodes. Once they have you need to top them at the highest point. This encourages lateral growth and will help you to achieve the best results with your ScrOG.
  3. Position the screen 20-30cm above the top of the pots and make sure that your light is centralised above the ScrOG net so as to offer an even light distribution to the plants.
  4. As your autoflowers grow and reach the bottom of your ScrOG netting you will need to gently weave them through the screen. Try to weave the plants through any empty squares to make best use of the available space. Don’t force any branches that don’t feel like they are going to easily bend, the aim of this method is to be gentle with the plant and cause as little stress as possible. Angle the branches in different locations to fill up any empty spaces and try to avoid overcrowding so that as much of the plants as possible has unshadowed access to light.
  5. Continue weaving the plant throughout the vegetative stage and use garden ties to fix the branches in place as you go. You can carry on weaving like this until the autoflowers just pass the early flowering stages.
  6. Once the plants have begun to produce noticeable buds avoid any more bending and weaving as this could damage the flowers. 

Sea of Green (SOG) approach

Sea of Green or SOG is a training technique with basically the opposite philosophy of the above two methods. Instead of growing a couple of plants and training them to grow big with multiple bud sites, you grow lots of smaller plants with fewer bud sites, using up every inch of your grow tent. On a plant by plant basis the yields are lower, but accumulatively they add up to a strong overall harvest. 

The benefits of using the SOG method to grow autoflowers is that it is a much lower maintenance approach than either ScrOG or the bend and tie method. This kind of approach with autoflowers would suit any cash croppers looking for a quick turnaround where the plants cannot be constantly monitored.

sea of green training autoflowers

Can you use HST with autoflowers?

Using HST (high stress training) methods such as mainlining, manifolding, supercropping and topping all cause more stress than LST. Some growers use these methods when growing autoflowers, however it is only recommended for experienced growers. Autoflowers have much shorter vegetative and flowering stages and so if a plant experiences stress it may not have enough growing time to recover before flowering begins. 

On average if a plant is stressed it can take between 5-10 days to fully recover and continue with normal growth. This can be detrimental to yields and cause stunted growth if the autoflower begins flowering before it has recovered.

Sticking to LST methods will cause less stress to cannabis plants and give you the best opportunity to get those massive yields. Once you have mastered the variations of LST training, you can attempt to give HST a go, although it is much less risky if done with photoperiods due to the increased recovery time that they have.

Joe Musgrave

Joe Musgrave is a keen 420 blogger who writes about all things cannabis. After harnessing his green thumbed skills through years of working on cannabis farms, Joe now shares his knowledge with the rest of the online 420 community.

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