Short answer. Let the plant reach 5–6 nodes, top it above the 3rd node, and remove everything below that node (the shoots and leaves at nodes 1–2). Train the two remaining arms horizontally. When each arm has grown 2–3 nodes, top each one again, giving 4, then 8, then 16 tops, all fed through one central "manifold" junction. The goal is perfectly equal colas in an even canopy. It costs roughly 2–4 extra weeks of veg (Grower practice). No study tests mainlining directly; the closest research found double pruning raised yield per plant and lower-canopy removal had no yield penalty in large plants [1].
How to do it
- Top above node 3 at 5–6 nodes; remove growth at nodes 1–2 (keep the node-3 pair).
- Tie the two arms flat, opposite each other.
- Let each arm grow 2–3 nodes; top each above its 1st node of new growth → 4 tops.
- Clean everything inside the hub that isn't one of the main arms.
- Repeat for 8 (and 16 in big spaces). Recover 5–7 days between rounds.
- Flip when tops are even and the space is ~70 % full.
Numbers that matter
| Item | Typical |
|---|---|
| Start | 5–6 nodes |
| Tops | 8 (common), 16 (large plants) |
| Extra veg | 2–4 weeks |
| Recovery per topping round | 5–7 days |
| Autoflowers | Not recommended |
Common mistakes
- Starting on a weak plant.
- Uneven arms (one arm dominates for the rest of the grow); correct with LST early.
- Flipping too early with tiny arms.
Evidence
Technique is Grower practice. The architecture logic (even canopy in good light, pruning increasing per-plant yield) is Supported [1][2].
