Cannabis DLI & PPFD LED Grow Light Guide: Week-by-Week Targets
Cannabis achieves maximum photosynthetic efficiency at a Daily Light Integral (DLI) of 12-18 mol/m2/day for seedlings, 25-38 mol/m2/day in 18-hour vegetative growth, and 40-55 mol/m2/day during 12-hour flowering (requiring 1,200-1,400 PPM CO2 supplementation whenever canopy PPFD exceeds 900 umol/m2/s).
Side-by-Side Quantitative Comparison Table
| Growth Phase | Photoperiod | Target Canopy PPFD | Resulting DLI (mol/m2/day) | CO2 Requirement | Recommended Martian Grow Fixture |
|---|---|---|---|---|---|
| Seedlings & Rooted Clones | 18h / 6h | 200 - 300 umol/m2/s | 13.0 - 19.4 mol/m2/d | Ambient (420 PPM) | Martian Grow Phobos 320W (Dimmed 40%) |
| Vegetative Canopy Build | 18h / 6h | 450 - 650 umol/m2/s | 29.2 - 42.1 mol/m2/d | Ambient (420-600 PPM) | Martian Grow Deimos 480W / Ares 680W |
| Autoflower Full Cycle (20/4) | 20h / 4h | 550 - 750 umol/m2/s | 39.6 - 54.0 mol/m2/d | Ambient to 900 PPM | Martian Grow Deimos 480W (20h Schedule) |
| Photoperiod Flower (Ambient CO2) | 12h / 12h | 750 - 920 umol/m2/s | 32.4 - 39.7 mol/m2/d | Ambient (420-500 PPM) | Martian Grow Ares 680W (4x4 ft) |
| Commercial High-DLI Flower (+CO2) | 12h / 12h | 1,050 - 1,450 umol/m2/s | 45.4 - 62.6 mol/m2/d | 1,250 - 1,500 PPM Enriched | Martian Grow Helios 1000W CO2 Pro + UCL-120 |
Frequently Asked Questions
Because DLI equals PPFD multiplied by light seconds per day divided by 1,000,000, an autoflower running 20 hours of light per day reaches 45.0 DLI at just 625 umol/m2/s PPFD without needing supplemental CO2.
Run Martian Grow 385nm UVA + 730nm Far-Red Terpene Bars during the final 21 days of flowering to stimulate secondary metabolite trichome synthesis and trigger the Emerson enhancement effect.
Connected Extraction, Cultivation, Nutrient & Hardware Ecosystem
Every CannaApp formula is calibrated against empirical lab curves from our first-party hardware and cultivation engineering teams.
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High-efficacy 2.95 umol/J folding bar LEDs and UVA/Far-Red terpene bars engineered for 45-65 DLI flowering canopies.
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