Best LED Grow Lights for Cannabis Flowering
Cannabis flowering starts when the dark period reaches 12 hours. During flower, a plant needs more light than in veg. Two numbers matter: PPFD at the canopy and daily light integral (DLI). A common target is 600 to 1,000 µmol/m²/s at 12 inches to 18 inches above the canopy. That gives a DLI of 26 to 43 mol/m²/day. A 2021 study in Frontiers in Plant Science found flower yield rose as DLI increased from 15 to 30 mol/m²/day. Above 30, returns per extra mole drop in some trials. Exact cultivar response varies. No standard exists for every strain.
How to Choose the Best LED Grow Lights for Cannabis
Top pick: Mars Hydro FC-E4800
The FC-E4800 is a 480 W bar fixture. Manufacturer lists 2.8 µmol/J, Samsung LM301B diodes, Osram 660 nm diodes, and a Mean Well driver. Dimming runs 0 to 100 percent. Bar layout spreads light across a 4 ft by 4 ft flower area. Check the current PPFD map on the listing before purchase.
LED Grow Lights for Cannabis: Review and Comparison
Runner-up: Spider Farmer SE5000
The SE5000 is a 480 W bar fixture. Manufacturer lists Samsung LM301B diodes, a dimmable driver, and coverage for a 4 ft by 4 ft flower area. It runs cooler than older quantum boards. Spectrum adds 660 nm red to a 3000K white base.
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Small tent: HLG 350 Diablo
HLG lists the 350 Diablo at about 340 W. It uses a bar layout and a dimmable driver. Coverage target is a 3 ft by 3 ft to 4 ft by 4 ft area. It suits a 3 ft by 3 ft tent with one plant or a 4 ft by 4 ft tent with low plants.
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Budget: Mars Hydro TS1000
The TS1000 is a 150 W quantum board. Manufacturer lists 2.3 µmol/J. Flower coverage is about 2.5 ft by 2.5 ft. It fits a 2 ft by 2 ft or 2 ft by 4 ft tent. One unit covers one to two plants in flower.
What to check before you buy
- PPFD map at 12 inches, 18 inches, and 24 inches. Look for a 4 ft by 4 ft grid with no dark corners.
- DLI at 12 hours. Aim for 30 to 40 mol/m²/day for flower.
- Efficiency in µmol/J. 2.5 or higher is good for 2024.
- Driver brand. Mean Well and Inventronics are common.
- Dimming. A knob or screw driver dimmer helps in late flower.
- Heat. Bar fixtures spread heat. Check for a fan or passive design.
- Warranty. 3 to 5 years is standard for bar fixtures.