High-Stress Training (HST)

High-stress training (HST) is a cannabis-growing method that helps you get the most out of your plants. It can increase your cannabis plants’ yield and the amount of THC in their buds. 

It is, however, risky because it has the potential to cause your plants to become overstressed. Worry not; this step-by-step high-stress training guide will help you avoid that problem.

High Stress Cannabis Training
High Stress Cannabis Training

What Is High-Stress Training (HST)?

As the name suggests, high-stress training involves intentionally cutting or wounding your cannabis for several benefits, such as increased yield and increased THC levels. High-stress training typically occurs before entering the vegetation phase, but you can still apply HST during their vegetation phase.

Growers cut, bend and break the stems of their cannabis plants to apply stress, which will then cause the plant to alter the way it grows. If applied correctly, the plant will recover and thrive. 

There are a couple of ways to perform this method since there are different high-stress training techniques. The main ones are:

Of course, other high-stress training techniques like Screen of Green (“Scrog”) involve trimming and manipulating your plants into growing outwards using a screen that you lay on top of them.

There’s also Lollipopping, where you prune the lower growths on your plant like you would with Scrogging, but only once your cannabis has developed bud sites.

When applying high-stress training, the key thing to keep in mind is to avoid over-pruning your plants. Give it time to heal after you use any of the techniques.

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The science behind this reaction ties in with apical dominance, a phenomenon in plants where the main stem outcompetes the branches in growth and nutrients. When the main stem is pruned along with its apical bud, it signals increased growth on the lateral buds.

By altering your cannabis plants to grow multiple buds, you create several other benefits in addition to increasing yield. For example, many believe that with high-stress training cannabis, you increase THC (and CBD) levels within the buds.

It also has the added benefit of better shape. HST causes plants to grow into a shorter, well-branched plant that gets equal light and wind exposure.

Although there’s a myriad of benefits attached to high-stress training weed plants, there are also a series of risks that you face if not prepared.

Risk of High Stress Marijuana Training
Risk of High Stress Marijuana Training

The Risks Associated With HST

Applying any kind of high-stress training on your weed plants opens the possibility of problems that could hinder growth, cause contamination, lead to less yield, or all of the above.

Hermaphroditism is the most common problem that’s brought on by overstressing weed. It’s also one of the main arguments made against high-stress training weed plants. It’s a valid one since once your weed hermies, you would have lost any potential yield from it.

The real problem with hermaphrodite weed plants is that they can potentially pollinate the rest of your weed garden, which means you would lose not just one plant but likely the entire batch. 

The ten strains we’ve selected in this article are what are known as Indica dominant strains, meaning that they contain a majority of Indica genetics, but also have some Sativa genetics and properties as well.

It’s also challenging to assess how much stress a weed plant can handle since some strains handle stress better than others, which is why you must pick a strain that can handle HST.

Even then, you should be careful. Check the condition of your plants and see whether or not HST should be applied.

If you apply it to a sickly or recently recovering plant, it could lead to permanent damage. This will reduce your yield and cause the plant to take longer to mature.

Outside of checking the conditions of your plant, assessing and being meticulous about items like scissors, ties, and other tools that you use on your plants is also essential.

Remember, if you don’t use sterile scissors, the pruned parts of your plant may develop molds and other marijuana diseases that would contaminate your harvest.

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When Should You Start High-Stress Training?

If you plan on applying high-stress training on your cannabis, you should do it before or during their vegetation phase. You should opt to apply HST before your weed plants enter their vegetation phase for the best result.

Topping, mainlining, and super cropping are a few great examples of HST applied before or during the plants’ vegetation phase.

Topping should occur before your plants enter their vegetation phase when they are less than 2-3 weeks old. You’ll also be able to tell when the young cannabis plants are ready once there are at least 2-5 lateral growths (nodes) on them.

The technique with topping also applies to mainlining. The only difference is that you  need  to trim the lower lateral growths below the 3rd node.

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Mainlining can then be applied once your plants have been topped if you want a more evenly distributed light among the branches. The only added step with mainlining is to prune the lower growths below the 3rd node of your plant. 

You’ll then need to let your plants veg for 6 to 8 weeks or at least once 3-4 new nodes have developed from the lateral growths you left. Afterward, you then top the new growths. Rinse and repeat until you have your desired amount.

If you find that mainlining is a bit too tedious, you can opt for super cropping, which is a much simpler way of evenly distributing the branches of your cannabis. 

With this technique, you only need to break and bend the top stem of your cannabis plants at a nearly 90-degree angle. Doing that disrupts the apical dominance of your plant and, with repeated attempts, will result in evenly distributed branches.

HST during flowering
HST During Flowering

Can You HST Plants During Flowering?

It depends on the type of HST you plan to apply to your already flowering cannabis plants. If it’s anything like mainlining and topping, then no.

Doing so would only be detrimental to your yield since your flowering cannabis is now focused on developing its buds. HST will disrupt this.

However, this is not always the case since you can apply high stress training during flowering. Two great examples are lollipopping and defoliation.

Both techniques work on the same concept of removing useless growths on your plant so that it can focus on the buds. 

In the case of lollipopping, it’s a bit more intense as you remove the lower growths that didn’t grow any buds during the early weeks of flowering. Defoliation is the best option if you want to play it safe since you only need to trim your plant’s leaves.

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Performing High-Stress Training

With knowledge about HST techniques and how to apply them, now you can put them into practice. However, before you do, there are a couple of things that you’ll need to keep in mind.

Think of this as the last section in our step-by-step high-stress training guide.

Choose A Healthy And Appropriate Plant

You must choose a hardy and healthy plant for applying HST. You need to have a keen eye in spotting any signs of poor growth on your plants –  especially when you’re applying pre-flowering HST techniques like defoliation and lollipopping. 

Know what is safe to cut and what isn’t since some of the leaves of your cannabis plant will begin to turn yellow naturally. (This is especially true with some sativa and sativa dominant strains).

Don’t let that deter you from pruning, though, as it’s not a sign that your plants are unhealthy; it’s, in truth, a sign that your plants are putting most of their energy into growing the buds.

Lastly, don’t apply HST on autoflowers. HST doesn’t apply well to the genes of cannabis ruderalis, which is a gene that allows cannabis strains to mature and flower quickly.

HST won’t work because it requires time for your plants to recover after applying it.

Choose Your Method Of Training

If you’re going for pre-veg or vegging marijuana plants, choose HST techniques like topping, mainlining and super cropping.

On the note of super cropping, it’s also applicable to cannabis already in their pre-flowering phase, but if you want the best result, stick to the vegetation phase.

For pre-flowering and flowering phase cannabis, you can use lollipopping and defoliation.

Scrogging works well with lollipopped plants since it involves spreading the lateral growths outwards.

This means you should continuously prune lower growths on the plant.

Cannabis has thousands of strains that produce an endless variety of hybrids. Checkout our guide on most common cannabis hybrids!

Monitor Your Plant

Lastly, you should carefully monitor the condition of your plants after you apply any of the following HST techniques. Look for any signs that aren’t right, such as greyish white coatings around the pruned parts of your plants. 

These are not trichomes; they are mold – and they’re difficult to spot since they blend well with the glittery hairs of your cannabis plants.

Outside of that, check if your plants have hermied by observing the buds. If you find any that don’t have hairs coming out of them, it’s a pollen sac.

Remove the plant from the rest of your batch if you want to avoid pollinating them. There’s no salvaging a hermied plant, even if you try to remove the pollen sacs.

LST And HST Cannabis Plants
LST And HST Cannabis Plants

Can You LST And HST Cannabis Plants?

Low-stress training (LST) involves bending and directing the growths of your cannabis plant with ties. This method spreads the growths of your cannabis evenly, allowing for equal distribution of light.

A popular example is topping after pruning the apical bud of your cannabis.

This spreads the lateral growths. After that, tie the growths down. In fact, you could say that mainlining and manifolding are just topping with LST. In the same way, you can say that ScrOG is just lollipopping with a screen on top of it.


The wonderful thing about the various growing techniques you can apply to cannabis is that there are so many of them. 

If you know the strain you’re growing, whether it be a sativa strain or indica strain, there’s a high-stress training technique that you can apply to it – as well as a low-stress training which you can pair with it.

If you’re looking for the perfect seeds to grow and train, has a large selection of regular cannabis seeds to help you grow like a pro.

FAQs About High-Stress Training

Is HST safe for cannabis plants?

If you have a good idea of what you’re doing and choose a healthy and hardy plant to apply HST on, then yes. If anything, it’s good for them as some strains are known to grow bushy, and need pruning to get enough breeze and avoid overcrowding.

What are some specific high-stress training techniques?

There’s a myriad of different high-stress training techniques such as mainlining, FIMMING, and super cropping. There’s also lollipopping and topping, which can be paired with LST. If you want to know more about growing techniques, we suggest you look into our guide about advanced growing techniques.

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