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Low Stress Training (LST) Tutorial
by Nebula Haze
Key Takeaway: LST (Low Stress Training) is a cannabis plant training technique to gently bend young plants and tie them down as they grow. This naturally creates multiple bud sites so you harvest far bigger yields! LST also allows you to force cannabis plants to grow into a shape and size you want - even if you only have a tiny grow space!
Example: All this bud is growing on a single 18" tall plant in someone's homemade grow box!
(this wouldn't be possible without LST/plant training)
Table of Contents
- Top Your Plant (optional)
- Create a "Star" Shape from Above
- Next Steps - Strategy for LST in Veg & Flower
What is LST and what does it mean for cannabis growers? What's the difference between "low" stress training and "high" stress training when it comes to growing cannabis plants?
There are other free cannabis plant training techniques that are more "high stress" such as cutting off the top of the plant. But LST is different and will not stress your plant or slow down growth much, if at all.
LST is a free, gentle & effective training technique for all cannabis plants
The idea behind LST is to 'bend' and otherwise gently manipulate the plant so your plants create multiple new colas for buds to grow on. Low Stress Training also lets you produce plants that grow in the exact shape and size you want, giving indoor growers much bigger yields from the same grow lights.
The LST technique can also be used on plants that are getting too tall for your setup, or are growing taller than your other cannabis plants. LST allows you to keep an even canopy and get the most from your grow lights.
Benefits of Low Stress Training
Bigger yields from the exact same grow lights and setup
Complete control over height, shape and size of plant
Plants produce multiple colas instead of just one
This plant is about a foot tall but is engulfed in fat buds.
Now take a look at the "guts" of this plant to see how this shape was achieved with LST
The main stem was first bent down and away from the center of the plant, towards the side. After that, the grower continued to bend the main stem in a circle around the plant. As a result, several lower growth tips rose up to become colas with fat chunky buds, giving much bigger yields than if there was just one main cola.
LST allows a better distribution of light since the the all parts of the plant (and all the buds) are about the same distance from the grow lights, so you can get more of your plant in the bud-producing "sweet spot" for your grow lights.
Colas the proper distance from your plants (in the "Sweet Spot" for your grow lights) produce the most amount of bud.
Wait, what distance should my grow light be from my plants? What's the sweet spot for my particular grow light? Learn what you need to know about grow lights here: http://www.growweedeasy.com/grow-lights
The percentages on the sides of the following diagram describe how much light is getting to your plants according to the Inverse Square Law of Light Intensity.
As you can see, the light intensity drops off fast as you get further away from the lights! You need training to get more buds in that sweet spot.
In the above diagram, you can see that the natural plant (left - completely untrained) has less parts of the plant in the best light. As a result, only the one main bud got significant yields. The rest of the buds on the natural plant are much smaller since they aren't getting nearly as much light.
The trained plant (right - which has been topped and trained with LST) has many colas that are directly in the sweet spot. In fact, almost the whole plant is getting bathed in just the right amount of light from the grow lights. This is how that plant was able to create so many huge buds - each one is close to the top of the light's "sweet spot."
Why settle with just one big cola when you could have many huge colas?
Low stress training involves bending unruly branches and using gardening wire or soft ties to hold the branches where you want them.
The majority of growers use LST are trying to keep their plants short and wide to take advantage of grow lights (or possible the sun), which means that you want to bend any branches down and secure them away from the other branches, so you're creating a wider canopy with many colas for bud to grow out of.
Bend too-tall branches down and away from the center of your plant. Tie them down.
This plant was big enough for us, so we waited a few days and switched to the flowering stage. Here's that plant a little less than a month later
By creating multiple colas, we were able to get a lot more bud off this plant (ended up getting about 6 ounces off this one under a 600W HPS light) than if we had let it grown naturally.
Now you know what to do if your plant is getting too tall. If your plant is getting too wide, bend side stems around your plant
A top view shows the "skeleton" of the plant, revealing how this plant was kept so short. This grower only had a small 2'x2'x3.5' grow space, so they only a few feet of height in the grow space, and even less width for the plant to splay out. After using LST to keep plant short, they used more LST and bending around the sides to keep it from getting more than 2' wide at any part of the plant, while making sure all buds were directly exposed to light.
When growers LST their plants, the general idea is to gently pull branches away from the middle of the plant, so that the plant looks like a star when viewed from above. This helps expose the lower branches to more light, while also keeping plants short.
Many growers cut or pinch off the tops their plants before starting LST work. This is not necessary but can be helpful. The reason for pinching off the tops is it breaks the apical dominance of the cannabis plant, giving you several main colas in one cut, and providing a more symmetrical base of the plant for training.
However, any cutting technique is not actually considered LST. LST is simply the act of actually bending and manipulating stems. Other plant training techniques can be used alongside LST to get the best results, and cutting the plant when it's young is one of the most popular ways to "set the stage" for LST. But cutting your plant isn't for every grower. In this article's step-by-step LST tutorial below, I'll walk you through the entire process of how to LST cannabis plants including any special plant training techniques.
Here's a great LST example by Santacabrera showing how to gently bend the middle colas of a plant down and away from the center without cutting the plant. Instead of cutting off the main cola, he simply bent it over like all the other side branches
Auto-Flowering Strains: Those who are growing auto-flowering strains need to skip the cutting part and go straight to LST (this is also mentioned in the cannabis LST tutorial, so don't worry if you forget). Auto-flowering plants are a special type of strain that you can only get from specialized seed breeders. Auto-flowering plants go through their entire life in just 2-3 months, so these plants usually don't have a long enough vegetative period for the plant to recover from a cutting/topping technique. Learn more about autos here: http://www.growweedeasy.com/autoflowering-vs-photoperiod
After a stem is bent over on the plant, each of the growth nodes on the stem can become new colas if they're exposed to light and air
Eventually all the growth tips on a horizontal branch will start growing upward toward the light. After initially bending your plant, growth may slow down for few days as the plant recovers, especially if stems are damaged in the process. But usually with LST there's little to no recovery time and the plant gets right back to business as usual. Often times they'll be pointing back up at the light in just a few hours.
As an added benefit, one of the plant's natural reactions to being extremely bent over is to stop trying to grow the main cola as much, and spreading out the energy to all the growth tips instead of just one. This gives you the power to craft the shape of your plant like an artist.
If you plan on using LST, I highly recommend getting a spool of plant ties, twisty tie or coated wire to tie your plants down with. There are many options available at your local gardening store or online, or you can rig something together yourself. More on that below.
Don't use string or anything sharp to tie down plants for LST!
Anything sharp can cut into your plants as they grow bigger, which you don't want. Open wounds are not good for cannabis growth. But soft wire ties, twisty ties, or anything soft and bendable will work perfectly without hurting your plants.
Twisty ties are good for smaller stems
Soft wire ties are much stronger and can hold on in almost any situation
The stems you bend over with LST can be tied to weights, to the pots your plants are in, your hydroponics bucket, or most anything. It's wire, so it can be easily hooked around branches without having to tie anything and get your hands in the plant.
Low Stress Training Encourages Plants to Grow More Wide and Bushy
As a result of the main cola being bent over, you tend to break the apical dominace, and all the lower branches will start rising up to become colas too.
Some growers also gently bend flexible branches until they snap slightly or crush the bent part between their fingers to cause slight damage to the bent point. This technique is known as super cropping.
Basically you're training the plant to grow into the shape you desire, like a marijuana bonsai tree. You train the plant slowly and take care not to hurt you plant. You don't want to snap any of the branches, and never try to bend stiff branches or they'll just break off.
If you accidently hurt the plant, and you create an open wound, it's important to tape up the wound to keep it closed while also providing support to the stem. The tape acts like a bandage and cast for your plants wound.
If you wound the outside of a stem while bending, tape it up immediately! Most of the time your plant will recover just fine.
By using this method alone, you can grow a plant that conforms to nearly any shape that you want.
A young vegetative cannabis plant
Plant twisty ties
Soft wire ties (optional) - only get these if you're going to grow very large plants; they're overkill for small plants
Note: You Must Skip This Step If You're Growing an Auto-Flowering Strain!
Read the full tutorial on how to top your cannabis plant or use the following quick guides:
The purpose of any cannabis cutting technique is to break the apical dominance of a cannabis plant. When you cut the "trunk" or main stem of a cannabis plant, the plant tends to start branching out and allowing lower growth tips to rise up and become colas.
Topping makes it easier to LST a cannabis plant, since you're given a more symmetrical "platform" to build your base off of instead of working just with one main stem.Using the topping training technique will encourage your plants to start growing more wide and bushy.
I prefer to top my plants when they've grown 6 nodes, although some growers top earlier. I top plants down to the 3rd node, which forms a more symmetric base compared to topping higher up on the plant. With topping you always end up with two main colas that split at the same place on the stem.
Why wait until the plant grows 6 nodes if you're going to top down to the 3rd? If you top your plant too early, it can stunt growth and your plant may take a while to recover. A vigorous plant that has already 6 nodes will recover quickly from topping, but a younger plant can sometimes be stunted for weeks from a single topping.
Although it may seem counterintuitive, letting the plant grow 6 nodes first will make the whole process go more smoothly, and it will likely take less time too!
Top Down to the 3rd Node
As we explained earlier, "topping" means to cut off the top of a plant or stem. In the picture below, the top of the plant has been removed, so that only 3 nodes (pairs of fan leaves) are left.
When topping, leave a little part of the old stem above the topping point. I know this may be hard for those who want to make everything completely even and neat. But leaving a little extra stem will help prevent your “elbows” from splitting until they have thickened.
The little growth tips nestled in the V of each fan leaf will become your new colas, so be careful not to injure them!
After this, it's time to let your plant grow naturally for a while, until it's grown several new nodes on each of the two main growth tips.
Topping does slow down the growth of the plant for a few days, and if you want to top more times for more colas, you'll end up adding extra time onto your grow compared to using just bending/LST, and honestly topping even a single time is going to get great results, especially when combined with LST.
Note: Some growers will top multiple times to create a "manifold" at the bottom of each plant. Learn more about manifolding: http://www.growweedeasy.com/manifold
It is essential that you start any Low Stress Training as soon as possible. It's best to start when your plant is very young, though with LST, it's better late than later, and better later than never.
The main idea is to keep all the stems about the same distance from the light. So you want to continually bend the tallest stems down to the level of the others, and use twisty tie to secure it in place.
You can simply bend your plant in the direction you want it to go
Another basic technique is to create a "star shape" from above. As your plant grows, you bend stems down and away from the middle of the plant, tie them down.
If you were unable to or chose not to top your plant, you need to bend over the main stem. Here's two examples of what that looks like:
Always bending the tallest stems down results in plants with a flat canopy
Some strains/branches will bend more easily than others. Young growth is almost always easier to bend than old growth.
Bend Stems When They Are Still Young and Flexible!
If you're going to LST your plants, you'll get the best results by starting early since it's easy to bend stems when they're young and flexible. As stems get older, they become hard and woody, making them difficult to bend without breaking!
You can tie down branches with anything, though plant ties (soft twisty tie made specifically for the garden, found at most gardening stores) works perfectly since you can easily bend it to any shape you want.
Common Ways to Secure Plants
Plant ties <-- Best, in my opinion
Soft wire ties <-- For very tall or large plants - it's overkill for small plants
I've seen people use pipe cleaners, coated wire, and more. You can use almost anything soft*
* It's best not to use anything sharp/thin (like string) on your stems to secure your plants - it will end up cutting into the plant and causing damage later, especially when the stems start thickening.
Time for Bending!
How exactly do you bend your plants?
The main ideas to keep in mind...
Be Gentle - Always bend very slowly and carefully. You can always bend more, but you can't undo a broken stem
Only bend soft growth - Newer growth is soft and pliable, so it is easily bend to your will. It's important to focus only on bending the newer, most flexible parts of the plant to avoid breakage. If a stem feels stiff, it will likely break if you try to bend it.
Start Training Early - Start low stress training early in the plant life so you can avoid every having to try to bend thick stems. If you keep on top of plant training from the beginning, you will only even need to bend new growth and it will go much more easily.
Make Sure Ties Are Securely Attached to Plant - Don't let wires or ties "scrape" or slip across the surface of a stem because it can cause abrasion (imagine something rubbing all over your skin until it gets raw). If you're having difficulty getting a specific stem to stay down without slipping, try to secure that stem in more places so all the stress isn't being placed on just one part of the stem.
I like to use plant ties and sometimes soft wire ties for really strong plants. I usually bend the wire to form a hook on each end. I hook one end to a branch, and the other to my pot, or anything else you can think of.
Choose a too-tall stem that you want to bend over
Check to make sure the stem is bendy where you plan to bend it - if it's too stiff to easily move, choose a place higher up on the stem
Turn the end of a twisty tie into a hook and gently hook it around the stem
Hook the other end of the plant tie to the container after stem is bent as much as you want - this will hold the stem in place
Repeat for any other stems that are taller than the rest
This grower uses plant ties to LST a cannabis plant, and he demonstrates all the above steps
Basically you're training the plant to grow into the shape you desire, further creating your own cannabis bonsai tree. Always bend stems slowly and take care not to hurt you plant. You don't want to snap off any of the branches, so never try to bend stiff branches; they'll just break off.
How to Secure Ties to the Sides of the Container
If you picked something made for plant training, like plant ties or soft wire ties, it can be a lot easier to secure your ties since these can be bent to hook onto almost anything
Some growers drill holes around the top of their plant containers so that ties can be secured through the holes
With fabric pots, the sides can be pierced (for example by safety pins) and ties can be attached to the safety pin
Attach ties to fishing weights, and use them to hold down branches
I've seen some growers stick something deep in the soil and use that as an anchor to attach ties to.
You can really get creative about this!
Don't tie down your plants in such a way that you won't be able to tend them or move them! You'll regret it later! For example, don't secure ties to something on the ground, or something else in the grow space. Try to make a self-contained container that you can pick up and move without disturbing any of the ties. This is why so many growers attach ties to the sides of their containers.
Since the tie is attached to the pot, the entire plant can be picked up and moved without accidentally pulling out ties, breaking stems, or otherwise messing up the LST job
Another example of hooking your ties to something that will always remain attached to your plant and its container
You will not be able to train your plant just once and that's it. The plant training process needs you to watch over your cannabis plants so you can slowly create the shape you're looking for. It also helps you quickly spot any unruly branches so you can bend them over before they get too stiff.
One thing to remember, bent stems immediately "realize" they're on their side and any part that is not tied down will start growing upwards again. The unbound parts of the plant will have straightened themselves out in just a few hours for a healthy plant. If you check your plants a few hours after bending, you'll be able to see exactly what I mean.
This is a pic of a cannabis plant immediately after an LST session - most of the stems are on their side
17 hours later, all parts of the plant not tied down have stood back up
Because of the quick recovery time experienced by cannabis plants in the vegetative stage, LST can be used to create short, bushy plants in a very short amount of time.
No matter how you secure your plant, the main idea is for it to hold down the branches in the shape that you want, while still allowing you to easily tend to your plants as they gets bigger.
That's worth repeating, don't tie down your plants in such a way that you won't be able to tend them or move them! You'll regret it later!
If you accidentally snap a stem, tape it up immediately like a cast - the plant will quickly heal itself as long as the two broken ends of the stem are held firmly together
With LST, you'll get the best results if you check on your plant at least every few days to see if any stems are out of place, so you can quickly bend them over where you want.
Continue to LST your plant throughout the vegetative stage until you get the height, width and shape you want.
You're ready to start flowering when...
You’ve transformed your cannabis plant into a horizontal table
You've reached half your desired plant height (since the plant may double in size after the switch to the flowering stage)
Learn how to initiate the flowering stage by changing the light schedule: http://www.growweedeasy.com/light-schedules
LST In Flowering Stage
When a cannabis plant is switched to the flowering stage, it can double in height within just the first few weeks. This is known as the "flowering stretch."
But all that new growth needs to be controlled so you can maintain the amazing canopy you've been working on throughout the plant's life!
So once your plant starts flowering, you should continue to watch out and use LST for the first few weeks, if needed, while your plant goes through her final growth spurt. During this period you need to be very careful to avoid touching new buds as much as you can. But don't worry if it happens a little - we're only human :)
After the first month of flowering, your work is pretty much done as far as LST. Phew! Now you get to sit back and just wait for your buds to fatten up. At this point, your plant is putting all her energy into making flowers/buds, and your plant structure will not change during the last several weeks of flowering.
After the first month of flowering, it’s best to only use LST as a last resort or in an emergency, like when you have a troublesome stem that is cutting off light to other parts of the plant, or if a cola has grown too close to the grow lights.
It is NOT recommended that you start LST in flowering. Proper LST must begin when the plant is in the vegetative stage, because by the time you get fully into the flowering stage, the majority of the plant structure has already been formed.
If you’ve LST’ed properly in the vegetative stage, your plant should naturally start growing rows of colas along the flat table you produced, and you’ll get plants that produce bigger yields from your same grow lights.
These two plants produced nearly a pound and a half under a 600W grow light due to LST and other plant training methods
(view the full grow journal on this harvest)
As you spend time training and observing your plants, you’ll begin to get a much better understanding of exactly what you're working with. I highly recommend viewing some cannabis time-lapse videos to get a better idea of how the cannabis plant grows: http://www.growweedeasy.com/marijuana-time-lapse-videos
That's it! You now have all the tools you need to become an LST master!