Flowering Stage — week by week from 12/12 flip to harvest

Flowering is the most demanding phase. Small mistakes halve the yield. Complete guide through the 8–10 weeks.

TL;DR: Wk 1–3 stretch (VPD 1.0–1.3, EC 1.6–2.0). Wk 4–6 bulking (EC peak 2.0–2.4, PK boost). Wk 7–8 ripening (drop T°). Final week: flush pure water. Harvest at 10–30 % amber trichomes.

The 12/12 flip

<12 h light = autumn signal. Total darkness at night: >2 lux = herm risk.

Wk 1–3 — Stretch

50–100 % stretch. Flower nutrients NPK ~1-3-2, EC 1.6–2.0. First pistils end wk 2. Last defoliation window.

Wk 4–6 — Bulking

Peak mass and trichome density. Light 900–1200 μmol, VPD 1.2–1.5, RH <55 %. PK boost wk 5–6.

Wk 7–8 — Ripening

Trichomes clear → cloudy → amber. Drop night T° to 18–22 °C, 8–10 °C differential for color.

FAQ

How long is flower?

Indica 7–9 wk, hybrid 8–10, sativa 10–14, autoflower 8–11 from seed.

Do I need to flush?

Yes with mineral nutrients, no with living soil.

Larfy buds?

Too little light, T° >30 °C, N excess in flower, or sativa without SCROG.