Cannabis Training Techniques Compared: LST, Topping, FIMming, SCROG & Mainlining

Full comparison of every major cannabis training technique — LST, topping, FIMming, SCROG, mainlining, and super cropping. Which technique maximises yield for your setup?

Why Training Is the Highest-ROI Skill in Cannabis Cultivation

Training costs nothing but time yet consistently delivers 30–60% yield increases over untrained plants. The reason is simple: indoor lights don't penetrate more than 12–18 inches into a canopy. An untrained plant with a single dominant cola wastes 70% of your light on lower growth that will never produce dense buds.

Training flattens and widens the canopy so every bud site receives direct light. Done correctly, a trained plant in a 4x4 tent can double the yield of an untrained plant under identical conditions.

This guide compares every major technique so you can choose the right approach for your grow style, space, and strain type.

Training Technique Comparison Table

LST (Low Stress Training): Best for Beginners and Autos

LST involves bending and tying stems horizontally to create a flat, even canopy without cutting the plant. It's the only technique appropriate for autoflowers because it causes no recovery downtime.

How to LST:
1. When the plant has 4–5 nodes, gently bend the main stem toward the pot rim
2. Secure with soft plant ties or garden wire (never wire that cuts into the stem)
3. As new growth rises vertically, bend and tie each new branch outward
4. The goal is a flat "manifold" shape with all bud sites at equal height

When to start: Week 2–3 for photoperiods, week 2 for autoflowers
When to stop: First signs of flowering (pre-flowers or pistils appearing)

For a detailed step-by-step guide, see our Complete LST Guide.

Topping vs FIMming: Cutting for Multiple Colas

Both techniques involve cutting the growing tip to redirect growth hormone (auxin) from the main cola to lower branches, creating multiple dominant colas instead of one.

Topping: Cut the entire growing tip (newest node) cleanly. Creates exactly 2 new main colas from the node below. High reliability, easy to execute, very predictable result.

FIMming (F*** I Missed): Cut approximately 75% of the newest growing tip, leaving the base. Creates 3–5 new colas instead of 2. Less predictable result, more growth sites, but requires 1–2 extra days recovery.

Key rule: Only top/FIM a healthy plant with 5+ nodes. Never top within 2 weeks of switching to flower. Never top autoflowers unless they're showing exceptional vigour in week 3 — the recovery time cost is rarely worth it.

Combine topping with LST for maximum yield — top once, then LST all resulting branches into a flat canopy.

SCROG and Mainlining: Maximum Yield Techniques

SCROG (Screen of Green): A horizontal net or screen is placed 10–15 inches above the pot. As branches grow through the screen, they're tucked horizontally until the screen is 80% full, then flipped to flower. Every hole in the screen becomes a bud site at the same canopy height.

SCROG is the highest-yield technique for 4x4+ tents. A well-executed SCROG in a 4x4 tent can yield 400–600g with a good 400W LED. The main limitation is that you can't easily move plants once the screen is filled — plan your grow space before installing.

See our Complete SCROG Guide for detailed setup instructions.

Mainlining: A highly structured technique that creates exactly 8 or 16 identical colas from a single plant. Involves topping at the 3rd node, removing all lower growth, then topping each resulting branch again at the 3rd node. Creates a perfectly symmetrical plant with equal light distribution to every cola.

Mainlining requires 2–3 weeks extra veg time and significant skill. It's not recommended for beginners but produces extremely consistent, dense, uniform colas.

Frequently Asked Questions

What is the best training technique for cannabis beginners?

LST (Low Stress Training) is the best starting technique. It requires no cutting, causes minimal stress, works on autoflowers, and can increase yield by 20–40% over untrained plants. Simply bend and tie the main stem and branches horizontally to create a flat canopy. Combine with topping once you're comfortable with LST.

Should I top or LST cannabis?

Ideally both — top once in early veg to create 2 main colas, then LST all resulting branches into a flat canopy. Topping alone creates multiple colas but leaves them bunched together. LST alone creates a flat canopy but from a single growth tip. Combined, they create multiple evenly-spaced colas across the entire pot surface.

Can you train autoflowers?

Yes, but only with LST. Autoflowers start flowering on a genetic timer (not light cycle), so techniques requiring recovery time — topping, mainlining, super cropping — risk the plant entering flower before recovery is complete. LST can be applied from week 2 to the first signs of pre-flowers without any recovery penalty.

What is the difference between topping and FIMming?

Topping removes the entire new growth tip, reliably creating 2 new colas. FIMming removes approximately 75% of the new tip, creating 3–5 new colas but with less predictability. Topping is simpler and more consistent. FIMming creates more tops but requires a slightly more precise cut. Both are done at the same growth stage (5+ nodes).

When should I start training cannabis?

LST: Start when the plant has 4–5 nodes (typically week 2–3). Topping/FIMming: Wait until 5–7 nodes are present and growth is vigorous (week 3–4 for most photoperiods). SCROG: Install the screen before veg growth reaches it; start tucking once branches extend 2–3 inches through. Never train within 2 weeks of switching to flower.

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