Training Techniques: LST, Topping, FIMing, and SCROG

Unmanipulated cannabis plants grow in a classic Christmas tree shape — one dominant central cola at the top receiving the most light, with progressively shorter, lower-yielding side branches below. Training techniques interrupt this pattern, redirecting the plant's energy to create multiple main colas of equal height and equal access to light, dramatically increasing overall yield without any increase in lighting or space.

LOW-STRESS TRAINING (LST)

LST involves gently bending and tying plant stems to alter the plant's shape without damaging tissue. The goal is to create a flat, horizontal canopy where all bud sites receive equal light. The process:

1. As the plant develops its first 3–5 nodes, begin bending the main stem gently away from the centre and securing it to the pot rim with soft ties or plant clips.
2. As secondary branches grow, bend and tie them outward in a similar pattern, creating a radial spread around the pot.
3. Maintain ties as needed throughout vegetative growth, adjusting regularly as the plant grows.

LST is the most forgiving training method — it can be reversed if mistakes are made, and it does not stress the plant significantly. Ideal for beginners and for autoflowering varieties, which do not tolerate high-stress techniques well.

TOPPING

Topping involves cutting off the main growing tip (the apical meristem) of the plant, which causes the two side branches immediately below the cut to take over as dominant growth points, effectively splitting one main cola into two. Subsequent toppings split four into eight, eight into sixteen, and so on. The result is a plant with multiple main colas of roughly equal size and height.

Topping causes significant stress and should only be performed during vigorous vegetative growth. The plant requires 3–7 days to recover from each topping before resuming normal growth. Do not top autoflowers — they lack the vegetative recovery time to benefit from the technique.

FIMing (F*** I Missed)

FIMing is a related technique where the growing tip is pinched or cut incompletely, removing only 75–80% of the tip rather than the entire growing point. The result is the growth of 4 (rather than 2) dominant growth points from a single cut — less predictable than topping but capable of producing more branches per intervention.

SCROG (Screen of Green)

SCROG involves suspending a horizontal mesh or trellis screen 20–30 cm above the pot canopy and training growing branches through the screen's openings as they grow. When the screen is 70–80% full, the plant is switched to flowering. As buds develop, they push up through the screen and are supported by it. SCROG maximises light use efficiency by creating a perfectly flat canopy and is one of the most efficient techniques for maximising yield per square metre.