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Training Cannabis Plants: Topping, LST, and ScrOG for Beginners
An untrained cannabis plant grows one tall main cola and a skirt of smaller, shaded buds. A trained plant grows a flat table of main colas, every one of them sitting in the best light you paid for. Training is that transformation, and in veg you have three honest tools for it — topping, low-stress training, and a ScrOG net. They combine, they are all learnable in one grow, and this guide walks each one in the order to use them.
Why training creates more tops
A cannabis plant is programmed to bet on one leader. The growing tip of the main stem produces a hormone signal that tells the branches below it to stay in their place — botanists call it apical dominance, and it is why untrained plants take the Christmas-tree shape: one dominant top racing for the sky, lower branches politely shorter. Outdoors under a moving sun that shape works. Indoors, under a stationary light that fades with every inch of distance, it means exactly one bud site gets the best seat and everything below is in the cheap seats.
Training is the art of cancelling that bet. Cut the leader off (topping), or bend it down to the same height as the branches (LST), and the plant's growth energy redistributes to the side branches, which begin growing like leaders themselves. Instead of one main cola and a supporting cast, you get four, six, eight tops of near-equal size, all living at the same distance from the light. The yield logic is not magic: more of the plant in the high-PPFD zone, and light hitting leaf directly instead of passing a tall top on its way to shade.
Training also buys control. A flat, wide plant fits a short tent that a Christmas tree never would, finishes with buds of even ripeness, and lets air pass through the canopy — which, after Guide 11, you know is mold prevention by other means. The tools below differ only in how they cancel the leader's vote.
Topping, step by step, with timing
Topping is one clean cut that turns one main stem into two. Timing and plant health matter more than technique: do it on a photoperiod plant in veg, once it has grown 4 to 6 nodes (a node is where a pair of branches leaves the stem), is growing vigorously, and shows no deficiency or pest problem — you are scheduling surgery, and patients should be thriving. Earlier than 4 nodes risks a stunted runt of a plant; much later wastes the shape you could have had.
- Find the main stem's growing tip and count down to the node you will cut above — the 4th or 5th node is the usual choice.
- With clean, sharp scissors or a sterile blade, cut the main stem just above that node, leaving a short stub of stem (a quarter inch or so) rather than cutting flush — the stub protects the fork as the two branches below thicken.
- The two branches at that top node now become your two main leaders. Give the plant its normal water and light and leave it alone.
- Expect a pause of several days while the plant reroutes its growth, then visibly faster growth from the two new tops. Most plants are fully back to speed in about a week.
- Optionally, top again once each new leader has grown a few nodes of its own — two tops become four. Each extra round adds veg time, so let your tent size, not enthusiasm, decide.
One cousin worth naming: fim-ing pinches the tip rather than cutting the stem, and can produce three or four tops from one site, less predictably. It is a fine second-grow experiment; topping's clean, predictable two is the better first lesson.
LST: bending instead of cutting, beginner-safe by design
Low-stress training does with patience what topping does with scissors: it persuades the leader to share. You bend the main stem over — gently, in stages, over a day or two if it resists — and tie it down so its tip sits at the same height as the side branches, or lower. The plant reads the geometry and promotes the branches. No wound, no recovery week, and if you dislike the result you can simply untie it: LST is the reversible training, which is what makes it the right first tool and the only one this guide endorses freely for autoflowers.
Work with soft ties — coated garden wire, fabric strips, or purpose-made soft ties — never bare wire or string that can saw into a growing stem. Anchor ties to the pot's rim (binder clips on a fabric pot rim make movable anchor points), bend branches outward like spokes to open the plant's center to the light, and re-adjust every few days as growth re-aims itself upward; a tied branch will try to turn its tip back to the sky within a day, which is the signal it is healthy and negotiating. Start when the plant is young and its stems are still flexible — bending a woody, late-veg stem is how branches snap, though even a snapped branch, splinted and taped promptly, very often heals.
The mindset that keeps LST safe: a little bend, often, beats a big bend once. You are guiding a living structure over weeks, and the plant does most of the work between your visits.
ScrOG: the net does the training for you
Screen of Green — ScrOG — is LST with infrastructure. A net or screen with roughly 2-inch squares is fixed horizontally above the pots, typically 8 to 12 inches above the medium, and the plant grows up into it. Every time a top pokes a few inches through a square, you gently pull it back under and lay it into the next empty square outward. The net enforces the flat canopy for you, spreading one plant across a wide footprint of even, top-level bud sites.
- Set the net before the plant needs it — retrofitting a screen over a big plant is a wrestling match.
- Veg the plant into and under the net, tucking tops outward to fill squares evenly, a few minutes every couple of days.
- Flip to 12/12 when the net is about 70 to 80 percent full — the flower stretch (Guide 6) will fill the rest.
- Keep tucking through the first week or two of stretch; after that, let the tops rise through the net as buds, and use the net as their support.
- Clear the shaded growth beneath the net — leaves and shoots down there get no light and only trap damp air; growers call this lollipopping, and under a ScrOG it is close to mandatory.
ScrOG asks for commitment: a netted plant cannot come out of the tent for watering adjustments or a pest inspection from behind, and the method suits one strain at one height per net. In exchange it produces the most even canopy in this guide, and for a single plant in a 2x4 or 3x3 tent it is arguably the highest-yielding honest technique a beginner can run.
The training-by-week timeline
| When | Do | Notes |
|---|---|---|
| Seedling weeks 1–2 | Nothing — hands off | The plant is building roots; all training now is harm |
| Early veg (3–4 sets of leaves) | Start gentle LST on flexible stems | First bends small; the main stem can be leaned, not folded |
| Veg, at 4–6 nodes | Topping window (photoperiods) | One clean cut; expect a 3–7 day pause |
| Mid veg | Continue LST adjustments; set the ScrOG net if using one; optional second topping | Space branches like spokes; keep the center open to light |
| Late veg | Final shaping; fill the ScrOG net to ~70–80% | Finish heavy work several days before the flip (Guide 5 checklist) |
| Flower weeks 1–2 | Last ScrOG tucks during stretch; support only | No more cutting of tops — from here the plant builds buds |
| Flower week 3 on | Ties for heavy branches, nothing structural | A branch bent by bud weight gets a string, not a training session |
What NOT to do to autoflowers
Every technique above costs the plant something — a pause, a wound, a recovery — and photoperiod plants pay those costs out of a veg period you control. Autoflowers pay out of a fixed account: their whole life is 10 to 12 weeks, the meter is running from sprouting, and a week spent recovering is a week of growth that simply never happens. So the autoflower rules are a shorter, stricter list. No topping for beginners — an experienced grower with a fast, thriving auto sometimes tops very early and gains by it, but the same cut on a merely average plant produces a small plant with two small tops. No ScrOG heroics, no heavy defoliation, no transplant-then-train stacking.
What autos do welcome is gentle, early LST: bending the main stem a little from the third week, opening the plant to the light with soft ties, adjusted kindly and often. That single technique, plus a final pot from day one and an undisturbed life, is the whole autoflower training program for most growers — and it is enough to turn the Christmas tree into a respectable bush without ever picking up the scissors.
Recovery times, and how to know it is working
Set expectations by the tool: LST barely registers — bent tips re-aim within a day and growth never visibly stops. Topping pauses upward growth for about 3 to 7 days while the two new leaders take over; judge success at a week, not at a day. ScrOG tucking stresses the plant least of all per session, because each tuck is small. The universal rules: never stack stresses on one day — topping, transplanting, and a heavy feed in the same afternoon is how sturdy plants slump; keep tools clean between plants; and do the work early in the light period so the plant has a full day of light to respond.
You will know training is working by geometry, not by hope: new tops appearing at the same height as the old leader, side branches thickening and reaching instead of trailing, light visibly reaching leaves that were shaded, and a canopy that reads as a table from the tent door. Take a photo from the same angle every week — the comparison teaches faster than any description, and it is the record that turns one grow's guesswork into the next grow's plan. That plan, plus everything before it in this series, leaves exactly one job undone: finishing the harvest, which is Guide 13.
Gear & seeds for this step
- Tools — snips, trimmers, and the small hardware of the training trade
- Soft plant ties on Amazon — the LST essential — soft enough to never saw a stem
- ScrOG nets on Amazon — elastic nets sized by tent; buy your tent's footprint
- Pruning snips on Amazon — clean cuts for topping — sharp and dedicated to the tent
- Media & pots — fabric pots whose rims double as LST anchor points
Frequently asked questions
Does topping really increase yield, or just change the shape?
It genuinely helps indoors, through light geometry rather than magic: two (or four, or eight) tops at the light's best distance out-yield one top at that distance plus shaded branches below it. The gains are real but bounded — topping cannot rescue weak light or a sick plant, and each topping round costs veg time, so in a very small grow a well-LST'd untopped plant can match it.
When is it too late to top a plant?
Top in veg, with at least a week of growth left before the flip — the plant needs days to recover and the new leaders need time to grow before they become flower sites. Topping after the flip, or in the final days of veg with no recovery room, trades buds you have for buds you will not get. If you missed the window, LST stays available longer and is the safer late tool.
Can I top an autoflower?
You can, and some experienced growers do — very early, only on a plant that is visibly outpacing its siblings, and accepting the risk. For most growers the honest answer is no: the auto's fixed clock turns the 3-to-7-day recovery into lost size, and gentle LST gets most of the same canopy benefit with none of the gamble. Learn training on photoperiods; let autos bend, not bleed.
I snapped a branch. Is it ruined?
Usually not — cannabis repairs breaks remarkably well if you act promptly. Realign the break, splint it with a stick or straw, tape or tie it snugly, and support the branch so the joint bears no weight. Kept aligned and still, many breaks knit within a week or two and go on to finish normally; a branch that wilts hard in the first day despite splinting is the one to remove cleanly.
How many tops should I aim for?
Let the tent answer: most small-tent plants finish happily with 4 to 8 main tops. Two toppings on a healthy photoperiod give four leaders; a ScrOG plant may present a top in most of its net's squares. Beyond your light's ability to feed them evenly, extra tops just subdivide the same harvest into smaller pieces — the goal is tops the light can finish, not a record count.