Cannabis Plant Training: LST, Topping, and ScrOG Explained
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Cannabis Plant Training: LST, Topping, and ScrOG Explained
A grower came in with a photo of a tall, lanky plant shaped like a Christmas tree, one big cola at the top crammed against the light and a tangle of weak, shaded branches below, asking what he had done wrong. The answer was nothing wrong, just nothing trained: left to itself, cannabis pours its energy into a single dominant top while the lower growth languishes. Plant training is how you fix that, gently reshaping the plant into a flat, even canopy where many bud sites get strong light instead of one, and it is widely considered the highest-return skill a grower can learn, often for the price of a few ties and a net. The trouble is the jargon, LST, HST, topping, FIM, ScrOG, mainlining, all thrown around at once. We sell the clips, wire, nets, and tools, so our interest is simply helping you train well, not selling you complexity. This guide is the map of every method, what each does, and when to use it, with links to our step-by-step deep dives. We don't upsell.
Think of this as the overview; each technique below links to its full how-to guide, and the whole thing fits into the timeline in our week-by-week grow guide.
The 30-Second Answer
- Training reshapes the plant into an even canopy so many bud sites get strong light instead of one dominant top, which can meaningfully increase yield.
- There are two families: low-stress training (LST), gentle bending and tying with no cutting and no recovery time, and high-stress training (HST), like topping, which cuts the plant and needs recovery.
- The three core methods: LST is the foundation, topping turns one cola into two, and ScrOG uses a net to build a flat wall of colas.
- Train during veg, ease off once flowers set, and only train healthy plants. For autoflowers and beginners, stick to LST.
Beginners and autos start with LST; add topping for more colas; use ScrOG to maximize yield per light. We carry the ties, clips, and nets and will point you to the right method. We don't upsell.
Why train cannabis? Apical dominance explained
To understand training, you first have to understand why an untrained plant grows the way it does. Cannabis exhibits apical dominance: the growing tip at the top produces hormones called auxins that suppress the side branches, concentrating energy into one tall central cola while lower shoots stay small and shaded. That is the Christmas-tree shape, and indoors under a fixed light it wastes much of the plant's potential, since only the top gets strong light. Training breaks or redistributes that dominance, whether by bending the top out of the way or cutting it off, so the plant spreads its energy across many shoots and forms an even canopy where every bud site sits at a similar height in strong light. The payoff is more and bigger colas from the same plant and light. This is not just folklore: cannabis researchers note that growers alter plant architecture to reduce shading and improve light penetration to the canopy, and a major yield meta-analysis emphasizes that output should be judged as yield per area, a gap closable with better cultivation methods rather than simply more space. Training is one of the cheapest ways to close that gap.
LST vs HST: the two families of training
Every training method falls into one of two camps, and understanding the split makes the rest simple. Low-stress training, or LST, means gently bending and tying branches into position without cutting or wounding the plant; because there is no injury to heal, the plant keeps growing without interruption, and the technique is reversible since you can untie and reposition at any time. High-stress training, or HST, means deliberately cutting, pinching, or crushing the plant, as in topping, FIM, mainlining, and supercropping; this triggers a stress response and forces a recovery period of roughly five to ten days before growth resumes, but it can reshape the plant more dramatically and push the yield ceiling higher. The trade-off is straightforward: LST is lower-risk, beginner-friendly, and safe for autoflowers, while HST offers bigger structural changes at the cost of recovery time and a little more risk. Most experienced growers use a combination, building structure with HST early in veg and then shaping and maintaining the canopy with LST, and we will walk through each technique in that light.
Low-stress training (LST): the foundation
LST is where almost everyone should start, and it remains useful no matter how advanced you get. The technique is simple: as the plant grows, you bend the tallest stems down and outward and secure them with soft ties, so the plant spreads into a wide, flat shape rather than reaching straight up. You revisit every few days, bending any branch that pulls ahead of the others back down, until the canopy is level and many bud sites sit in the light. Because nothing is cut, there is no recovery time and no real risk beyond snapping a stem if you rush, which makes LST forgiving for beginners and the only training we recommend for autoflowers. Start while growth is young and flexible, since older stems turn woody and brittle. LST is also the backbone of other methods, since a topped or screened plant is still shaped with LST. For the full step-by-step, tie patterns, and timing, see our dedicated LST guide.
Topping and FIM: more colas from a cut
Topping is the most common high-stress technique and the fastest way to multiply your main colas. You cut off the plant's growing tip just above a node, which removes the source of apical dominance and forces the plant to push two new main shoots from the node below, turning one cola into two; top those again and you get four, then eight, multiplying your bud sites with each round. FIM is a close cousin, a less precise pinch that removes most of the tip and tends to produce three or four new tops rather than a clean two. Both are done in vegetative growth on healthy photoperiod plants, with sterile tools and a few days of recovery between cuts, and neither is recommended for autoflowers, whose fixed lifecycle cannot spare the recovery time. After topping, you typically use LST to spread the new tops into an even canopy. Our topping guide covers exactly where and when to cut, plus how topping and FIM differ in practice.
ScrOG (Screen of Green): a flat wall of colas
ScrOG, short for Screen of Green, is the method serious tent growers reach for to squeeze the most from a fixed light, and it is really LST taken to its logical conclusion with a screen. You install a horizontal net, commonly eight to twelve inches above the pots, and as branches grow up through the holes you tuck them back under and sideways, weaving the plant across the screen to fill it evenly before you flip to flower. The result is a flat, uniform canopy of many colas all sitting at the same height in optimal light, which is the most efficient use of a given light footprint and a reliable way to maximize yield per square foot. It pairs naturally with topping for even more, evenly spaced tops. The one real limitation is that once the net is in place and the plant is woven through it, you cannot move the plant until harvest, so plan your space first. Our ScrOG guide walks through net height, timing, and how to fill the screen.
Other techniques worth knowing
Beyond the core three, a handful of techniques round out the toolkit. Mainlining, also called manifolding, combines topping and LST into a deliberately symmetrical structure where every cola grows from an even manifold, producing a very uniform canopy at the cost of a few extra weeks of veg; it is an advanced extension of topping. Supercropping is a high-stress method where you gently crush the inner tissue of a stem and bend it, controlling height and strengthening the branch as it heals, useful for taming a plant that is stretching too tall. Lollipopping is a pruning technique rather than structural training, removing the small, shaded lower growth that would only produce wispy larf so the plant focuses on the strong upper colas. Defoliation, the selective removal of fan leaves, is also energy and airflow management rather than shaping, and it is more contested, with growers split on how aggressively to do it. Finally, Sea of Green, or SOG, is not really training at all but a layout strategy, growing many small plants flipped to flower early for a fast, uniform harvest. Most home growers do well focusing on LST, topping, and ScrOG before exploring these.
Training indoors vs outdoors
Where you grow shifts how you train, even though the principles stay the same. Indoors, under a fixed light with limited height, the goal is to fill the light's footprint with an even, flat canopy and to keep the plant short enough to stay in its ideal range, which is why LST and ScrOG dominate indoor training; you are shaping the plant to match a rectangle of light. Outdoors, with the sun overhead and often months of vegetative time, the goals change: you have room to build big, bushy plants, so growers lean on repeated topping and mainlining to multiply colas and on heavier, season-long LST to manage size and expose the interior to sun, while also training with wind and the eventual weight of buds in mind. An outdoor photoperiod plant can be topped several times over a long veg, where an indoor plant in a short veg might be topped only once or twice. The takeaway is to train toward your situation: indoors you fit the light, outdoors you build the plant, and the same toolkit serves both.
When to train across the grow
Timing separates training that helps from training that hurts. The vast majority of training belongs in the vegetative stage, when stems are flexible and the plant has time to recover and redirect its growth; this is when you start LST early, do any topping, and build your structure. Begin LST while the plant is young, around the third to fifth node, and if you are topping, do it on a vigorous plant in veg with recovery time between cuts. As you approach the switch to flower, do your final major tie-down about a week before the flip, because the flowering stretch, roughly the first three weeks of 12/12, pushes the canopy upward by fifty to a hundred percent depending on genetics. Keep making small adjustments through that stretch to hold the canopy even, then stop major training once flowers have set, since stressing a plant in mid-flower slows bud development. The principle is simple: shape in veg, fine-tune through early flower, then leave it alone to bloom, a rhythm our flowering stage guide follows.
Training autoflowers
Autoflowers deserve their own note, because they change the rules. Unlike photoperiod plants, autos flower based on age rather than light schedule, so they run on a fixed internal clock and cannot afford to pause, which means any technique that forces a recovery period costs you yield you can never get back. For that reason, the firm consensus is to train autoflowers with LST only: gentle bending and tying that never asks the plant to stop and heal. Start early, around day fourteen to twenty-one, keep your adjustments gentle, and stop any significant moves the moment you see the first pistils appear, since the plant is committing to flower. A light ScrOG can also work with autos since it is low-stress, but high-stress methods like topping, FIM, and mainlining are best avoided, as the five-to-ten-day stall they cause can noticeably shrink a short-lived auto's final harvest. With autos, always watch the plant rather than the calendar, and err on the side of gentleness.
How much yield increase can you expect?
It is fair to ask what training actually buys you, and the honest answer is meaningful but variable gains rather than a guaranteed number. Growers commonly report something like twenty to fifty percent more yield from a well-trained plant compared to an untrained one in the same space, and aggressive methods like ScrOG or mainlining can do better, but these are grower-reported figures, not lab-precise guarantees, and the real result depends heavily on your genetics, light, pot size, and skill. What is solid is the mechanism: training exposes more bud sites to strong light and improves canopy light penetration, which is well grounded in how plants convert light into yield. So treat training as a high-probability way to get more from your existing light, not a magic multiplier, and remember that it cannot overcome weak genetics, poor light, or a stressed plant. Pair good training with healthy plants and adequate light and the gains tend to show up reliably; expect improvement, not miracles.
Which training method should you use?
With the methods laid out, choosing comes down to your experience, your plant type, and your space. If you are a beginner, growing autoflowers, or running a single plant in a small space, start with LST alone, which is low-risk, effective, and teaches you to read the plant. If you are growing photoperiod plants and want more and better-distributed colas, add topping to your LST, the popular and powerful combination of a couple of toppings in veg with continuous LST between and after. If you are running multiple plants or a larger tent and want to maximize yield from your light, ScrOG is the method that pays off, especially combined with topping. And if you crave a perfectly symmetrical, showpiece canopy and have time to spare in veg, mainlining is the advanced route. There is no prize for using the most aggressive technique you can; the best method is the one that matches your plant and your patience, and you can always start simple and layer in more as you gain confidence.
Defoliation: how much is too much?
Defoliation, the selective removal of fan leaves, is the most debated technique in training, so it deserves a clear-eyed word. The case for it is real: removing old, large, or shading leaves in late veg and again in early flower can improve light penetration to lower bud sites and airflow through a dense canopy, and older leaves past their prime consume nearly as much energy as they produce. The risk is overdoing it, since leaves are the plant's engine, and stripping too many at once starves it of the photosynthesis it needs to grow and fill out buds. Aggressive timed defoliation, sometimes called schwazzing, is an advanced technique that experienced growers use deliberately, not a default. For most growers, the safe approach is restraint: remove only clearly old, damaged, or heavily shading leaves, do it sparingly around the flip and early flower, and never strip a plant bare. When in doubt, take less, because the plant will tell you quickly if you have taken too much.
Tools and safety
Training needs very little gear, but a few basics make it easier and safer. For LST and ScrOG you want soft, rubber-coated plant ties or dedicated LST clips, garden wire, and ideally fabric pots with grommets around the rim to anchor ties, plus a trellis net for screening. For topping, FIM, and mainlining you need sharp, sterile scissors or pruners to make clean cuts that heal well, and it is worth keeping plant tape on hand to splint a stem if you snap one during supercropping or an over-enthusiastic bend. Beyond tools, a few safety rules protect your plants: only ever train healthy plants, never ones that are sick, pest-ridden, or nutrient-deficient, since training adds stress they cannot afford; bend slowly and only the young, flexible parts of stems, because you can always bend more but cannot un-snap a branch; give the plant recovery time after any high-stress cut before stressing it again; and avoid tying wire so tightly that it cuts into a thickening stem. Patience is the real tool here.
Combining techniques: the LST and topping method
In practice, the best results usually come not from a single technique but from combining a couple, and the most popular pairing is topping plus LST. The recipe is simple: top a healthy photoperiod plant once in veg to create two main shoots, optionally top again for four, allowing recovery between cuts, then use continuous LST to bend and spread those tops into a wide, even canopy as they grow. Many growers then run that trained plant up into a ScrOG net for the flattest possible wall of colas. This combination works because each method covers the other's gap: topping multiplies your main colas, while LST positions them evenly in the light, and the screen holds the whole canopy flat. It is more involved than pure LST but far more accessible than mainlining, and it is the workflow we would point most photoperiod growers toward once they are comfortable making a cut. Start with whichever single method suits you and layer in the others as your confidence grows, building toward the combination over a grow or two. We sell the clips, wire, and nets for all of it, and our only aim is helping you build the canopy your light deserves. We don't upsell.
Common training mistakes
Most training mishaps come from a short list of errors. The first is training an unhealthy plant, piling stress onto one already struggling, which sets it back further. The second is topping or otherwise high-stress-training an autoflower, costing it irreplaceable days. The third is doing too much at once with no recovery, stacking multiple stressful cuts in a short window. The fourth is impatience in bending, forcing an old woody stem until it snaps instead of working young growth gradually over a couple of sessions. The fifth is training too late, making major changes in mid-flower when the plant should be left to bud. The sixth is ignoring the flowering stretch, building a tidy canopy then letting it grow lopsided as the plant shoots up in early bloom. And the seventh is over-defoliating, stripping so many leaves that the plant loses the engine it needs to grow. Avoid these, train healthy plants gently and on time, and the technique reliably pays you back.
What We'd Tell You at the Counter
If you asked us how to train your plants, our first move would be to keep it simple and match the method to where you are. For almost everyone, we would say start with LST, because it is nearly impossible to ruin a plant with gentle bending and it teaches you to read your canopy. If you are growing photoperiods and feeling confident, we would walk you through adding a topping or two in veg for more colas, and if you are running a tent for maximum yield, we would set you up with a ScrOG net. We would be honest that autoflowers should only ever get LST, that you should never train a sick plant, and that patience beats aggression every time, since a snapped main stem hurts far more than skipping a technique. We sell the ties, clips, nets, and tools, so our only goal is helping you shape a better canopy, not selling you the fanciest method. We don't upsell.
Frequently asked questions
Does training actually increase cannabis yield?
Yes, in a canopy-limited indoor setup it typically does, because training spreads the plant into an even canopy where many bud sites receive strong light instead of one dominant top. Cannabis researchers note that growers alter plant architecture to reduce shading and improve light penetration to the canopy, and that yield is best measured per area, which training improves. Reported gains vary widely with genetics, lighting, and skill, but growers commonly see meaningful increases over untrained plants in the same space. Training is one of the cheapest ways to get more from your existing light.
LST vs topping: which is better?
They do different jobs and work best together. LST is low-stress bending and tying with no cutting, so there is no recovery time, it is reversible, and it is safe for beginners and autoflowers. Topping is a high-stress cut that turns one cola into two but costs the plant five to ten days of recovery and is not suitable for autos. Many growers top a photoperiod plant once or twice in veg for more colas, then use LST to spread those tops into an even canopy. If you must choose one, start with LST; add topping once you are comfortable.
When should I start training my plants?
Start LST early in vegetative growth, around the third to fifth node, while stems are young and flexible and bend without snapping. Do any topping in veg as well, on a healthy plant, allowing recovery time between cuts. Make your final major tie-down about a week before flipping to flower, then keep making small adjustments through the early flowering stretch, which can push the canopy up by fifty to a hundred percent, before stopping major training once flowers set. In short, shape in veg, fine-tune through early flower, and leave the plant alone to bloom after that.
Can you train autoflowers?
Yes, but with low-stress training only. Autoflowers flower on a fixed age-based clock and cannot recover lost time, so high-stress techniques like topping, FIM, and mainlining, which force a five-to-ten-day stall, can permanently reduce their yield. Stick to gentle LST, starting around day fourteen to twenty-one and stopping major moves when the first pistils appear. A light ScrOG can also work since it is low-stress. The guiding rule with autos is to keep training gentle, start early, and watch the plant's development rather than following a fixed calendar.
What is the difference between LST and HST?
LST, low-stress training, means bending and tying branches into position without cutting or wounding the plant, so it keeps growing with no recovery period and the changes are reversible. HST, high-stress training, means cutting, pinching, or crushing the plant, as in topping, FIM, mainlining, and supercropping, which triggers a stress response and a recovery period of roughly five to ten days but can reshape the plant more dramatically. LST is lower-risk and beginner and auto friendly; HST offers bigger structural change for photoperiod plants at the cost of recovery time. Most growers combine the two.
Do I need to top my plant before using a ScrOG?
No, topping is not required for ScrOG, but the two pair very well. ScrOG works by weaving branches through a net to fill an even, flat canopy, and you can do that with an untopped plant trained purely by tucking and LST. However, topping first creates more evenly spaced main shoots to fill the screen, which many growers find produces a denser, more uniform wall of colas with less larf. If you are a beginner, you can run a ScrOG with LST alone; if you are comfortable topping, combining the two is a proven high-yield approach.
Will training stress or hurt my plant?
Done correctly on a healthy plant, training is safe and beneficial. Low-stress training causes no injury at all, while high-stress techniques cause a brief, manageable recovery period that the plant bounces back from stronger. The risks come from poor execution: training a plant that is already sick or deficient, bending old woody stems until they snap, stacking too much stress without recovery, or training too late in flower. Follow the basic rules, only train healthy plants, be gentle and patient, allow recovery after cuts, and train in veg, and the plant handles it well.
Whichever methods you choose, the soft ties, LST clips, garden wire, trellis nets, fabric pots, and pruners for training your canopy live in the Modern Farms catalog under grow accessories, and our team is glad to help you pick the right approach for your plants and your experience rather than sell you complexity. Training is the highest-return skill a grower can build, so use this as your map and dive into the step-by-steps with our guides to LST, topping, and ScrOG, make the most of your light with our LED grow lights guide, and time it all with the week-by-week grow guide. Because, as always, we don't upsell.
For informational and educational purposes only. This article is general horticultural guidance and is not legal advice. Cannabis cultivation laws vary by country, state and locality, and growing cannabis may be illegal where you live. Always understand and comply with the laws and regulations that apply to you before growing any cannabis plant.