Lighting — the #1 lever for yield and quality

Light is the only grow factor that scales yield linearly (up to CO₂ limit). Master PPFD, DLI and spectrum to squeeze every watt.

TL;DR: PPFD veg 300–600, flower 700–1000 μmol/m²/s. DLI 20–30 veg, 40–55 flower. LED (2.7 μmol/J) beats HPS (1.7) and CMH (1.9). Standard 30–40 W real LED/m² veg, 35–50 W flower.

PPFD, DLI, PPE

PPFD: μmol photons/m²/s. DLI: mol/day = PPFD × h × 3.6/1000. PPE: μmol per joule.

LED vs HPS vs CMH

LED: highest efficacy, full-spectrum, low heat. HPS: legacy, high heat. CMH: quality niche with native UV.

Spectrum

Blue 400–500 nm compact. Red 620–700 nm flower. UV 280–400 nm boosts trichomes final weeks.

Watts per m²

30–40 W real LED veg, 35–50 W flower. A 60x60 cm tent needs ~120–150 W real LED for flower.

FAQ

Real W/m²?

35–50 W real LED in flower. Ignore HPS equivalents.

Full-spectrum needed?

Recommended. Purple 15 % more efficient but no diagnosis possible.

UV worth it?

Yes, last 3–4 weeks flower, 2–4 h/day: +10–30 % trichomes.