when to start training autoflowers

When To Start Low Stress Training (LST) Your Autoflower

Low-stress training is a plant training technique used to train cannabis plants into the desired shape to maximize light usage and yields, among other benefits.

LST allows growers to control height and maximize yields without having to invest in new growing equipment and with relatively little work.

1. What is Low Stress Training?

Low stress training (also known as LST) is a technique used to train your weed plant into the desired result using the lowest amount of stress possible. There are also High stress training (HST) techniques like topping or pruning but we won’t be talking about them here as they tend to stunt growing for a short period of time and cannot be used with autoflowers as they have a determined life cycle.

2. When to Start Low Stress Training

There isn’t an exact age or size to start LST’ing autos, in theory, you can start as soon as the first true leaves grow, we recommend start training as soon as your plant can reach the edge of the pot, around 10-15cm or 4 – 6 inches (use this as a guideline, it mainly depends on the structure of your plant more than the size).

Before starting, you need to be sure you’ll benefit from it as it may have a toll on your autoflower, read a bit on how to LST autos, and always remember that you should not LST during flowering because it will stress your plant and decrease the yields.

Any kind of stress (even from overwatering) can ultimately ruin your harvest so make sure you really need to do it before starting any plant training method.

3. Why use LST?

LST is used to maximize output yield, maximize light usage, decrease the vertical space needed or just to control stretching using the least amount of stress possible.

Training Method Advantages
Tie-down Gives you the ability to control stretch and mold your plant anyway you want and need.
SCRoG Suited to even the canopy and increase the number of bud sites.
SoG Used to maximize limited growing spaces.

We recommend starting slowly training this autoflower at around week 3 and stop when you can’t notice any more growth, at this stage, she will only focus on bud production.

At Fast Buds we offer a wide variety of strains that perform outstandingly with LST, we particularly recommend one of our most popular strains to date Zkittlez Auto among others.

She develops a large main cola and a few lateral side branches, she tends to take a lot of nutrients resulting in a sturdy strain that will respond nicely to training and will grow multiple hefty colas throughout the plant.

TIP: When performing LST, start slowly and be careful not to hurt your plants. The best way is to bend it a little each day in order to get the least amount of stress, be patient, and don’t overdo it!

Maximize Yield Output

The overall yield of your autoflower plant can be increased by using LST, more light will get to the foliage, thus producing more food and resulting in denser buds.

More Dense Buds

Normally LST is needed to make buds on the lower branches denser, if no LST is performed you would need another light source. This is one of two ways of maximizing the overall yield when harvesting and also saving a couple of bucks.

Get Light to Lower Branches

Getting light to lower branches is another way to maximize yield and is especially good to perform with autoflowers because they tend to be smaller and bushier so this would result in not only more bud but also a better-looking plant overall.

Decrease Space Needed

Normally growers have a limited space to grow their autoflowers, this method is used to control the space your plant takes, especially if you have multiple plants in a small space. The best way to control space is by using the SCROG method and Tie down method will be explained in detail in the next topics.

Control Stretching

Sometimes when autoflowers don’t get enough light they tend to stretch and can get very bad, resulting in aery buds and can end up taking too much space.

Have in mind that you can also perform LST outdoors but usually is not needed because your plants aren’t limited by space.

4. Additional Recommendations and LST Techniques

have in mind that there isn’t such thing as the most effective LST for cannabis plants, there are several methods used when low-stress training such as SCROG, and the Tie-down method, and they should be used according to how your plants grow.

Both of them will have similar results and can be used for achieving what we covered earlier.

The Tie Down Method

The Tie-down method consists of making holes on the edge of your pot and use any kind of string (must be flexible) to bend and hold down your plant, usually starting with the main branch, your goal is to level all branches to the main cola.

For this plant training method we highly recommend trying out our Lemon Pie Auto, this high yielder can produce up to 550gr/m2 and develops a great structure with great internodal spacing that allows you to comfortably tie down the branches, increasing the yields.

By properly bending down the branches and shaping your cannabis plant, you will reach a structure similar to what you would get with a SCRoG net.

She is so heavy had to lay the plant on its side to cut and remove trellis so her branches and even main stem did not split. Sticky as she can be, had to clean hands and trimmers (eyes once lol) many times for just a light trim. Easy trim Excellent plant Fast Buds. – HisHope

The tie-down method doesn’t necessarily need to be used to even out your canopy, you can shape your plants either way you want, even just for controlling their height if you have a limited growing space.

Doing it properly will allow your plant to develop multiple bud sites that get equal amounts of light and result in better quality and bigger yields.


  • Easy and cheap.
  • No planning necessary.
  • No problem when moving your plants around.


  • You will have to tie each branch individually throughout your plant’s vegetative stage, which can be time-consuming.

The Screen of Green (SCROG) Method

The Screen of Green consists of using a net or type of screen, similar to a volleyball net, used to maintain branches to the same height by bending and holding the branches down.

This is a great method to spread out the canopy and take full advantage of your growing space, by spreading out the canopy your plant will develop bud sites that will get just the right amount of light to fatten up nicely.

One important element when talking about SCROG is genetics, depending on the plant structure you can have different results because some strains work better in this type of setup.

When Scrogging, it’s better to use one strain at a time and preferably a strain that grows shorter and with a lot of flowering sites.

Vertical SCRoG

A vertical SCROG is the best way to maximize your growing space, this method works by having a SCRoG net vertically that extends on to the sides of your growing tent.

By doing it this way you allow your plants to grow more bud sites and absorb all the light emitted by your light fixture, reducing light waste and enhancing your yields even more.

I have also used some more paper clips (XL sized ones) to pull side branches to the main stem, it works pretty darn well in keeping the plant upright because these buds are getting extremely heavy – some of the branches could not hold them up anymore. This also sort evened the canopy out a little, which is great of course. I think this will be a good harvest! – FrankieBones

Orange Sherbert Auto performs extremely well with LST techniques thanks to her Sativa heritage, perfect for vertical Scrogging. This lady is one of our tallest hybrids reaching up to 150cm (around 60in) and yielding up to 600 gr/m2 (1.3lb) therefore low-stress training is not only advised but recommended.

Low-stress training is a plant training technique used to train cannabis plants into the desired shape to maximize light usage and yields, among other benefits.

How to Train Auto-Flowering Plants for Bigger Yields

How to Use Plant Training Methods on Auto-Flowering Strains

For those who don’t know: An auto-flowering marijuana plant automatically starts making buds about 3-4 weeks from germination, and most plants are ready to harvest by the time they’re 3 months from seed. Auto-flowering strains produce plants that are ready to harvest earlier than almost every “regular” (photoperiod) strain and don’t need special light schedules. You generally only get auto-flowering seeds from a reputable breeder.

A Sweet Afghani Delicious (S.A.D.) Auto at 5 weeks old and 15″ tall – just a week away from harvest!

The quick-yet-bountiful harvest is one of the biggest benefits of growing auto-flowering marijuana plants. However, the shortened vegetative stage brings up an important question. Generally, when growing “standard” (photoperiod) strains, indoor growers use plant training methods for the first 4-6 weeks of a plant’s life to make plants grow flat and maximize yields in the flowering stage.

Can auto-flowering plants be “trained” in their short vegetative stage? And if they can be trained, does it actually provide any benefits? The short answer is “yes” to both questions (with one caveat)!

As Long as Plants Are Healthy, Auto-Flowering Cannabis Strains Usually Respond Well to Simple Topping or Low Stress Training

This gorgeous Hubbabubbasmelloscope auto-flowering plant was topped at a young age by a talented grower called awolace (who has many great grow journals on auto-flowering plants) and produced 4.75 ounces by itself.

Auto-flowering strains can be trained to produce more and bigger colas, and proper plant training can increase yields and overall improve your grow results.

Auto-flowering strains from a decade ago were heavily hybridized with wild hemp and produced small and subpar quality flowers. However, modern auto-flowering strains from trustworthy breeders (like this Auto Lemon OG Haze plant from breeder Nirvana) produce buds that are just as potent and beautiful as traditional photoperiod strains.

3 Main Schools of Thought on Auto-Flower Training

There are 3 main schools of thought about what works best when it comes to training auto-flowering cannabis plants:

  • No Training at All – Since autos only stay in the vegetative stage for a few weeks, if you stress your plant too much with extensive training, it may end up stunted. A stunted auto-flowering plant produces very low yields. As a result, many growers recommend no training at all when it comes to auto-flowering marijuana strains, just to be safe. Untrained plants still produce a lot of bud!
  • Low Stress Training Only (Bending) – The idea behind low stress training is to force the plant into the flat shape you want by bending all new stems and tying them down. The advantage of sticking only to bending is it’s very low stress (hence the name) on the plant. There’s basically no chance of stunting from simple bending. However, with LST you don’t have the same full control over the plant’s shape as you do when you actually “top” the plant (split the main cola into two), which makes it very easy to grow a wide and flat plant.
  • “Top” the Plant in Addition to Other Training – Modern auto-flowering strains often respond well to “topping”. This is when you cut off the very top of the main stem when the plant has only a few nodes, so that it grows two main stems instead of just one. This makes it easy to spread out the plant under the light. Topping usually won’t stress your plant if it’s healthy and fast-growing, but it’s possible that topping may contribute to stress or stunting if your plant is slow growing or sickly.

Most growers agree you don’t want to do aggressive training on an auto-flowering plant, for example you probably wouldn’t want to make a full manifold, which takes several weeks in the vegetative stage to set up. Though there are exceptions, you usually don’t have enough time in the vegetative stage to take full advantage of that kind of training technique with auto-flowering plants.

Example of a Stunted Auto-Flowering Plant

These auto-flowering plants were stunted when they were young by heat and overwatering. Now they’ve already started flowering and are just a few weeks from harvest.

Even though they have a plentiful amount of light, at this point the plants are not going to get any bigger no matter what the grower does because the vegetative stage is over, and the flowering stage is already under way.

Here’s a closeup of the middle plant. You can see by the bud development that it’s just a few weeks from harvest. Since it’s this far into the flowering stage, you know that the plant is not going to get any bigger. The buds will fatten up, but even if they tripled in size, the grower would only get a few grams of bud. The plant just isn’t big enough to support bigger yields.

This is why many growers recommend no training for auto-flowering plants. They’re trying to avoid stunting. But in the above example, the plants weren’t even topped. They were stunted from heat and overwatering, not training. So, I think the main point is to avoid stressing the plant when it’s young, not something as black and white as “no training allowed.”

Untrained Auto-Flowering Plants

Here are examples of untrained auto-flowering plants. With good care and a lot of light, they can produce a whole lot of bud without any training, especially the medium to tall strains!

These 5 auto-flowering plants were started at the same time. Without any training, they grew into this sea of buds at harvest! Growing many untrained plants together can be one of the easiest ways to get to a quick, hefty harvest. This style of growing is known as Sea of Green and is very well suited to auto-flowering strains.

Low Stress Training on Autos

Here’s an example of LSTing an auto-flowering plant by bending over the main cola when it was young and still mostly in the vegetative stage.

This allows the plant to be spread out in a way that’s somewhat similar to the result of topping

This auto also wasn’t topped. I only used bending and securing to try to keep it wide with many colas. I was happy in the end with the shape, but it was a big pain trying to keep it flat. It’s just a lot easier to keep plants flat when you top them, since it splits them and you can lay each side flat.

Without topping you end up making a “spiral” with the main stem to keep it as short as the rest. Here’s the “skeleton” of that plant to give you a better idea of what the training looked like underneath

An auto-flowering Super Skunk plant just before harvest – this plant spent a little over 2.5 months under a Mars LED grow light.

A view from the side of the same plant. Only LST/bending was used to keep it short and wide, and as a result you can see there’s still one dominant cola higher than the rest, even though the plant has been completely bent over.

Topping an Auto-Flowering Plant?

If you cut off the very top of a young, fast-growing auto-flowering plant, it may not even notice. Many growers recommend against topping an auto plant because stress can stunt your plant. While you definitely want to avoid stunting, I personally think topping autos works well as long as you make sure your plant is healthy and fast-growing first.

To be honest, other factors like overwatering or a poor environment seem to be much more likely to stunt an auto-flowering plant than topping, especially if you’re cutting off just the very tip of the plant without removing much plant matter.

Overwatering or a poor environment is far more likely to stunt an auto-flowering plant than a simple topping. For example, this auto-flowering plant was stunted due to overwatering and heat.

I’ve seen that many growers in our forum (check out photos from Green75 for some great examples!) have gotten great results topping their auto-flowering plants. I’ve also seen many growers (myself included) get incredible results with either no training or just low stress training! So, I definitely think you can succeed with any training style as long as you listen to your plants!

This Auto Amnesia Haze plant was topped, trained and defoliated. It already has a sea of buds with a month left to go until harvest!

When is the best time to top an auto-flowering cannabis plant?

Although you can top a plant any time it is still in the vegetative stage, I believe you will get the best results by removing the 3-5th node while it’s still tiny, as long as the plant is fast-growing.

This is about as old as an auto-flowering plant should be for topping

I think one of the most important things to avoid stunting is to remove as little as possible. The less you remove, the less the plant will notice.

I personally wouldn’t cut off more than this when topping an auto-flowering marijuana plant.

You could even have pinch the stem off a little higher, above those two baby fan leaves. The arrows point to the two growth tips that would be the new “tops” if you had cut where the red line is. In this case, you would have removed even less from the plant, reducing the chance of stunting even more, and helping your plant keep as much growth as possible.

This diagram shows where to cut for topping, along with where to expect the new main stems.

When is it a Bad Idea to Train an Auto-Flowering Plant?

Auto plants are on a very tight time schedule in the vegetative stage, and therefore plant training isn’t necessarily the best idea for plants that are already sick or stunted since they likely won’t have time to recover.

Don’t Train an Auto if…

  • Plant is Sick, Stunted, or Slow-Growing
  • Plant is older than 4-5 weeks old and has already started forming little budlets – after this point only use low stress bending and securing to keep the plant the shape you want

With an auto-flowering strain, you generally have about a month to create the main shape of the plant. After that it will start flowering and although it will continue getting taller, you want to let the plant focus on fattening the buds as opposed to a whole lot of further training.

If you’re not sure whether to top your plant, it’s recommended to stick to bending as it can achieve similar results without any risk of further stunting your plant!

That being said, almost every other plant training method (topping or FIMing, low stress training, supercropping and Sea of Green) can be used on auto-flowering plants as long as you watch the plant closely for signs of stress and make sure you let the plant get big enough to produce good yields in the flowering stage!

Extra Growing Tips for Autos

Low to Medium Nutrient Needs

Whether you grow in soil, coco coir, or a full hydroponic setup, auto plants often tend to prefer relatively low levels of nutrients compared to many other cannabis strains.

When it comes to adding extra bottled nutrients, start at 1/2 strength of the recommended dose or less, and only add higher levels of nutrients if needed. In hydro use “vegetative” nutrients until you see “budlets” (little bunches of white hairs) which is often around 4-5 weeks. In good soil, you don’t need to add any nutrients during the vegetative stage. After the first signs of buds, start adding “flowering” nutrients at very low strength (1/2 strength to start).

Potted Auto Plants

Potted auto plants tend to do best in an airy potting mix with lots of drainage (plenty of drainage holes, and something like perlite to help add more drainage to your growing medium). This helps makes sure roots get plenty of oxygen so plants grow as fast as possible.

With any soil mix, it’s recommended to have about 20-30% extra perlite for increased drainage.

Strain & Final Size Have an Effect on Training

The final size of your auto plants is largely dependent on the strain you get. Some strains, such as Lowryders, have been bred to grow extremely short – less than 1-2 feet. Other strains can grow taller, up to 4 feet tall or even more.

Although most auto strains start flowering at just 3-4 weeks, some strains take up to 8 weeks (or even longer) to auto. Often, long-flowering auto strains are labeled as “Super Autos” or “XXL” but you should still read the breeder description to fully know what to expect as far as timelines and height.

If you have a plant that is not “auto-ing” as soon as you want, you can put it on a 12/12 light schedule and it will usually start flowering in 1-2 weeks just like a photoperiod plant.

These two auto-flowering plants are the same age and were grown in the same setup! Genetics makes a huge difference to your final results, so it’s important to pick the right auto-flowering strain! The small plant is White Widow Auto & the huge plant is Onyx Auto.

These two auto-flowering plants are also the same age and grown in the same environment. The small plant is Auto Chemdawg & the huge plant is Super Lemon Haze Auto.

As a general rule of thumb, auto plants tend to double or triple in size from when they first start showing signs of flowering/budding (usually when plants are about 3-4 weeks old from seed).

Final Height of Auto-Flowering Plants is Often

2-3 Times the Height When the Plant First Started Showing Pistils

An auto-flowering plant is usually “full size” at just 6-7 weeks from seed! For example, these autos are 6 weeks old and didn’t get any taller, even though buds are still fattening and harvest is still several weeks away!

A stunted autoflower won’t produce much bud because it never gets big!

Bend too-tall branches down and away from the center of your plant

Plant training is a tactic that helps cannabis growers increase yields indoors by exposing more buds to strong, direct light from the grow light.

When growing any cannabis plants indoors, it’s recommended to at least use bending to open up the plant so it grows flat and wide

A view from the side just before harvest so you can see how those plants were trained to grow flat and wide. Training allows all the bud sites to grow directly under the light, so they get as big as possible

Recommended Auto-Flowering Strains and Breeders

Which breeders can you trust for good auto-flowering marijuana seeds? These auto breeders have dedicated themselves to developing auto-flowering strains in particular, and have gained popularity for their consistency and quality.

​There are many other breeders that offer auto-flowering seeds, but the breeders listed have become famous for breeding some of the best auto seeds when it comes to ease of growth, potency and yields. Let us know if you believe there’s an auto-flowering cannabis breeder we should add to this list!

Dinafem was one of the first breeders to go “all in” for auto-flowering strains when they started a comprehensive breeding program several years ago. Their award-winning Auto Sour Diesel strain produces average looking buds, but the strain was easily one of the most potent autos I’ve grown. In fact, every auto strain I’ve grown from Dinafem has produced above-average quality buds in smell, appearance and potency.

Auto Sour Diesel – bud look average but bud effects are unique and powerful!

Nirvana has several popular auto-flowering strains, but their latest auto strain Auto Lemon OG Haze has been getting some especially impressive results in bud quality, with a nice appearance, high THC and a medium amount of CBD. Their Auto Northern Light is another popular strain, especially with first-time growers, because it has a relatively low smell and is known for being easy to grow with good yields.

Sweet Seeds is known for colorful auto strains that are easy to grow, like their Dark Devil Auto and Black Cream Auto.

Examples of Different Possible Bud Colors on Black Cream Auto Plants

Over the last few years this breeder has really started becoming very popular for auto-flowering strains, and has made a name for producing amazing auto-flowering genetics. I’ve seen several beautiful examples of Mephisto Genetics in our forum but no one has formally submitted a picture yet! Send us your pics!

Is "topping" an auto-flowering strain ok? Does plant training increases yields? Auto-flowering cannabis strains actually respond very well to training as long as you do it right!