What is the best LED grow light for cannabis?
The HLG Scorpion Diablo is the best LED grow light for cannabis overall. It runs about 3.0 µmol per joule, spreads even PAR across a full 4x4 flower canopy, and pairs Samsung LM301H diodes with 660 nm deep red. Dimming, a five-year warranty, and US assembly make it the lowest-risk buy for a serious home grow.
Spider Farmer vs Mars Hydro for Cannabis: Which LED Grow Light Wins?
If you want a cheaper light with smart-app control, the Spider Farmer SE7000 is the better value for a 4x4 or 5x5. Both lights hit the PPFD numbers flowering cannabis needs, so the decision comes down to budget, coverage, and how much heat you can manage.
Best LED grow lights for cannabis at a glance
- Best overall: HLG Scorpion Diablo (4x4 to 5x5)
- Best for 4x4 tents: Spider Farmer SE7000
- Best value 5x5: Mars Hydro FC-E6500
- Best mid-range 4x4: VIPARSPECTRA KS5000
- Best smart controller pairing: AC Infinity IONFRAME EVO6
- Best budget: ViparSpectra P1000 or Mars Hydro TS1000 (2x2 to 3x3)
1. HLG Scorpion Diablo: best overall
Horticulture Lighting Group built this fixture around a 640 W driver and a 3.0 µmol/J photon efficacy rating, which sits near the top of the consumer market. The board covers a 4x4 area at flowering intensity and a 5x5 for veg without hot spots at the edges. Passive cooling and a remote-mount driver keep tent temps manageable.
highest yield led grow lights for cannabis
- Efficacy: roughly 3.0 µmol/J
- Coverage: 4x4 flower, 5x5 veg
- Spectrum: 3000K plus 660 nm deep red
- Warranty: 5 years
Downsides: the price is high, and you need a separate controller if you want scheduling and sunrise/sunset ramps.
2. Spider Farmer SE7000: best for 4x4 and 5x5 tents
The SE7000 pushes 730 W of bar-style LED with LM301H EVO diodes and bridgelux deep red, giving strong center-to-edge uniformity. Bars spread heat better than a single board, so a 5x5 tent with an exhaust fan stays in range. It ships with a dimmer and works with the Spider Farmer app controller for timing and intensity changes.
3. Mars Hydro FC-E6500: best value for a 5x5
The FC-E6500 delivers around 730 W across eight bars for a 5x5 flower footprint. It uses Bridgelux diodes with Samsung chips, and the smart driver adds app dimming, scheduling, and daisy chaining. Efficiency lands near 2.8 µmol/J, which is close to premium lights for hundreds less.
4. VIPARSPECTRA KS5000: best mid-range 4x4
The KS5000 spreads 500 W over a 4x4 with six bars and Samsung LM301H diodes, hitting roughly 2.7 µmol/J. It includes a magnetic dimmer box and daisy-chain ports for multi-tent setups. It is a good step up from budget boards without premium pricing.
5. AC Infinity IONFRAME EVO6: best for smart integration
If you already run an AC Infinity controller and inline fan, the IONFRAME EVO6 slots into the same ecosystem with one app. It offers around 3.14 µmol/J on a 500 W bar frame and covers a 4x4 flowering canopy. Automation is the selling point here, not raw wattage.
6. Best budget LED grow lights for cannabis
For a 2x2 or 3x3 tent, the ViparSpectra P1000 and Mars Hydro TS1000 both deliver usable PPFD at a fraction of the cost. Neither hits premium efficacy, and coverage falls off at the corners. They suit one or two plants in veg or a small flowering run.
How many PPFD and DLI do cannabis plants need?
Cannabis responds to light intensity across the whole cycle, so PPFD targets shift as plants mature. Keep seedlings and clones low to avoid stress, then ramp up as the canopy fills.
- Seedlings and clones: 100 to 300 PPFD
- Vegetative: 300 to 600 PPFD
- Flowering without CO2: 600 to 1000 PPFD
- Flowering with CO2 and dialed environment: 1000 to 1500 PPFD
Daily light integral (DLI) is the number that actually drives growth: 20 to 30 mol/m²/day in veg and 30 to 45 mol/m²/day in flower works for most home grows. Push higher only when temperature, CO2, water, and nutrients keep pace.
How many watts per square foot for cannabis LEDs?
Modern bar LEDs run well at 30 to 40 W per square foot of canopy. A 4x4 tent is 16 square feet, so 480 to 640 W is the target range. Older or less efficient fixtures may need closer to 50 W per square foot.
What to look for in a cannabis LED grow light
- Photon efficacy (µmol/J): 2.5 or higher is solid, 2.9 or higher is premium.
- Uniformity: Bar styles spread light better than single boards in square tents.
- Dimming: Essential for veg and for heat control in small rooms.
- Driver placement: Remote or removable drivers cut canopy heat.
- Safety listing: Look for ETL or UL marks and IP-rated connectors.
- Warranty: Three years minimum, five years on premium fixtures.
Frequently asked questions
Are cheap Amazon LED grow lights worth it?
Some are, if the listing states real diode brands, photon efficacy, and wattage drawn from the wall. Cheap lights often inflate "equivalent" wattage and use low-bin diodes that fade in a year. Verify the actual power draw and check reviews for par maps.
Do I need UV or IR diodes for cannabis?
Far-red 660 to 730 nm can influence flowering and stretch, and many premium fixtures include it. UV diodes are optional and can stress plants and skin, so treat them as an advanced tool. A solid 3000K or 3500K base with deep red covers most grows.
How far should an LED be from the cannabis canopy?
A strong 600 W bar light at 100 percent sits 18 to 24 inches above a flowering canopy. Seedlings need 30 to 36 inches or heavy dimming. Always confirm with a PAR meter or the manufacturer's PPFD chart instead of guessing.
Can one LED cover both veg and flower?
Yes, a dimmable full-spectrum fixture covers the whole cycle. Run lower intensity and a longer photoperiod in veg, then increase wattage and switch to 12/12 for flowering. A single 480 W to 640 W light is the most common setup for a 4x4 tent.