LST and Plant Training Basics

Why train cannabis plants

Untrained plants grow one dominant cola — fine outdoors with unlimited sun, wasteful under a square LED footprint. Training spreads the canopy flat so secondary branches become productive bud sites instead of popcorn below the shadow line.

More even canopy = more even light = better yield per watt indoors. Training doesn't replace good genetics or lighting — it maximizes what you already have.

Low-stress training (LST)

Bend branches gently and tie them horizontally with soft plant ties or coated wire. The goal is an even table of tops at roughly the same height, 8–12 inches below your light at mid-flower.

Start when the stem is flexible — usually after 4–6 nodes. Bend a little every day rather than snapping once. If a branch cracks, tape it — cannabis often heals.

• Tie from the pot rim, not the tent frame — plants move when watered
• Bend main stem early to break apical dominance
• Re-adjust ties every 2–3 days during stretch
• Works on autoflowers if started early and kept gentle

Topping and fimming (photoperiod mainly)

Topping cuts the main stem above a node, splitting growth into two mains. Do it after 4–6 nodes when the plant is healthy — not during stress. Wait 5–7 days before topping again.

Fimming removes ~75% of the new growth tip instead of a clean cut, often producing four tops. Sloppier but effective. Both increase site count at the cost of recovery time.

SCROG (screen of green)

A mesh screen 8–12 inches above the pot catches branches as they grow through. Weave new growth horizontally under the screen until the grid is ~70% full, then flip to flower (photoperiod) or let autoflowers bloom on schedule.

SCROG shines in 3×3 and 4×4 tents with one or two plants. It requires planning — you can't easily move plants once the screen is locked in.

• One plant per 3×3 SCROG is common for photoperiod
• Flip or wait until screen is mostly filled — not empty, not a solid mat
• Defoliate lightly under the screen for airflow after stretch settles

Defoliation — less is more

Strategic leaf removal opens airflow through dense canopies — especially before flower week 3. Fan leaves are solar panels; stripping them aggressively rarely increases yield and often slows recovery.

Remove leaves that block bud sites or touch soil. Skip the "full strip day" unless you know your strain tolerates it.