An untrained cannabis plant grows like a Christmas tree: one big cola on top, smaller ones down the sides, the lower half in shade doing very little. Training turns that into a flat, wide canopy of colas all at the same height under the light — which is the difference between 2 oz and 4 from the same plant, the same light and the same tent. None of it is difficult. Here's what each technique does, when to do it, and what not to do to an autoflower.
Why a flat canopy matters
Light intensity falls off fast with distance. A single tall cola 12 inches under the light gets full PPFD; the buds a foot below it get maybe a third. Spread the plant out so every bud site sits at the same height, and every one of them gets the full light. That's the whole idea; every technique below is a way of getting there.
Low-stress training (LST): the one everyone should do
Bend the stems down and tie them to the pot's rim or to stakes, so the plant grows outward rather than up. The tips turn back toward the light within a day, and the side branches that were shaded now get light and grow into colas of their own.
- When: start once the plant has 4–5 nodes and the stem is still flexible — around week 3 for photoperiods, week 2–3 for autos. Continue through veg and the first two weeks of flower.
- How: soft plant ties or garden wire with a rubber coating; anchor to holes punched in the rim of a fabric pot. Bend gently, a bit at a time; a stem that bends too far kinks (which usually heals, but slows things).
- For autos: this is the only training to do, and only early. It doesn't stall the plant and the payoff is real.
Topping: for photoperiods
Cut the main growing tip off just above a node. The two branches below it become two main colas instead of one; top those and you have four. It creates the even canopy directly, and combined with LST it fills a tent.
- When: at the 4th–6th node, in veg, on a healthy plant. Never in flower.
- Recovery: 3–7 days of slowed growth. That's the cost.
- Autos: generally no. The recovery week is a week the auto doesn't have, and the yield gain rarely covers it. Experienced growers top very vigorous autos at the 3rd–4th node with mixed results; a first grow shouldn't.
FIMing ("cut about 80% of the tip") is a variant that gives 3–4 tops instead of 2 and is less precise. Same rules.
SCROG: the net
A "screen of green" is a horizontal net a few inches above the pots; as branches reach it you tuck them under and along the squares, so the whole canopy ends up as one flat layer at net height. It's the most effective way to fill a tent from one or two plants and to control height in a short tent.
- When: install the net in veg once the plant is topped and spreading; keep tucking until 2–3 weeks into flower, then stop and let the buds grow up through it.
- The catch: once the plant is woven into a net you can't move it. Watering and inspection happen through the screen. Pot placement is final.
- Autos: a low net works if placed early; the plant is in flower before it fills much of it.
Defoliation and lollipopping: with restraint
Defoliation is removing fan leaves that shade bud sites or block airflow through the canopy. Lollipopping is stripping the lower third of the plant — the small, shaded, larfy growth that will never produce a bud worth trimming — so the plant puts everything into the tops.
Both are useful; both are overdone by beginners who've seen photos of stripped plants. Rules: take leaves that are clearly blocking a bud site or in a humid, airless spot; never more than 20–25% of the plant at a time; do it in veg and once around day 21 of flower, then stop. Lollipop just before the flip. A plant needs its leaves to make buds.
The schedule, put together (photoperiod)
- Week 3 of veg: top at the 5th node.
- Week 4: start LST on the two mains, tie outward.
- Week 5–6: top again if you want four mains; net goes on; tuck as it grows.
- Flip when the canopy is flat and fills 70–80% of the tent.
- Flower weeks 1–2: keep tucking under the net; remove lower larf.
- Flower week 3: last tuck, last defoliation. Hands off.
For an auto: LST from week 2–3, nothing else, hands off by week 5.
Height control in a short tent
If a photoperiod plant is going to run out of headroom: flip earlier (it'll double), net it low, and top instead of letting a single main run up. A plant that's touching the light gets bleached; a light that's raised to clear one tall cola starves everything else. Flat canopies fix both.
What to have
- Soft plant ties or coated garden wire, and a hole punch for fabric-pot rims.
- Bamboo stakes for tie-down anchors in a bigger pot.
- A trellis net sized to the tent for SCROG — or a length of garden netting stretched on the tent poles.
- Sharp, clean scissors for topping and defoliation.
The one-line version
Bend it flat with ties, top it once or twice if it's a photoperiod, net it if you want to fill the tent, and take only the leaves that are genuinely in the way. Autos get gentle tie-downs and nothing else. A flat canopy under the light is what the yield comes from.
As an Amazon Associate we earn from qualifying purchases made through links in this guide — at no extra cost to you. Picks are ours; prices and stock are Amazon's.