LED grow lights have revolutionized home growing, but the market is flooded with confusing specs and misleading claims. This guide cuts through the marketing hype to help you choose the right light for your grow space.
Why LED?
Modern LED grow lights offer significant advantages over older HID (HPS/MH) technology:
- Energy efficient: 40-60% less electricity than HPS
- Less heat: Easier climate control, closer to plants
- Long lifespan: 50,000+ hours (10+ years of growing)
- Full spectrum: No need to switch bulbs for veg/flower
- Quiet: No ballast hum, just small cooling fans
Specs That Actually Matter
1. Actual Wattage (Not "Equivalent")
Ignore "1000W equivalent" claims. Look for actual wall draw. A quality LED pulling 100-150W from the wall is perfect for a 2x2 tent. For a 3x3, aim for 200-300W actual draw.
2. PPF and PPFD
PPF (Photosynthetic Photon Flux): Total light output in micromoles per second (μmol/s). Higher is better, but coverage area matters more.
PPFD (Photosynthetic Photon Flux Density): Light intensity at a specific distance, measured in μmol/m²/s. This is what matters for your plants. Target PPFD values:
- Seedlings: 200-400 μmol/m²/s
- Vegetative: 400-600 μmol/m²/s
- Flowering: 600-900 μmol/m²/s
3. Efficacy (PPE)
Measured in μmol/J (micromoles per joule), this tells you how efficiently the light converts electricity to usable light. Budget lights: 1.5-2.0 μmol/J. Premium lights: 2.5-3.0 μmol/J. Higher efficacy = lower electricity bills.
4. Spectrum
Full-spectrum "white" LEDs are now the standard and work great for veg and flower. Some lights add supplemental red for flowering or UV/IR for trichome production. For beginners, standard full spectrum is perfect.
Calculating Coverage
A rough rule of thumb: 30-50 actual watts per square foot for flowering.
| Tent Size | Minimum Watts | Ideal Watts |
|---|---|---|
| 2'x2' (4 sq ft) | 100W | 150W |
| 2'x4' (8 sq ft) | 200W | 300W |
| 3'x3' (9 sq ft) | 225W | 350W |
| 4'x4' (16 sq ft) | 400W | 600W |
LED Types
Quantum Board Style
Flat boards covered with Samsung or similar diodes. Even light spread, efficient, run cool. Examples: Mars Hydro TS series, Spider Farmer SF series, HLG boards.
Bar Style
Multiple LED bars spread across a frame. Premium option with excellent coverage uniformity. Examples: Gavita, Fluence, Spider Farmer SE series.
COB (Chip on Board)
Older technology with intense point-source light. Can cause light burn if too close. Less common in 2025 but still effective.
Budget vs Premium
Budget (<$100): Mars Hydro TS600/1000, VIPARSPECTRA. Good for starting out, lower efficacy means higher electricity costs long-term.
Mid-range ($100-250): Spider Farmer SF1000/2000, Mars Hydro TSW2000. Sweet spot for most home growers. Good efficiency and features.
Premium ($250+): HLG, Gavita, Spider Farmer Pro. Best efficiency, build quality, and warranties. Worth it for serious growers running multiple cycles.
Our Top Picks by Tent Size
2x2 Tent: Mars Hydro TS1000
150W actual draw, perfect coverage for a single plant. Dimmable, full spectrum, great value around $80.
3x3 Tent: Spider Farmer SF2000
200W draw with Samsung LM301 diodes. Excellent efficiency at 2.5 μmol/J. Around $200.
4x4 Tent: Mars Hydro FC-E4800 or HLG 480
480W bar-style light with uniform coverage. For the serious grower wanting maximum yields.
Common Mistakes When Buying LEDs
- Believing "equivalent" wattage: Only actual draw matters
- Buying based on Amazon reviews alone: Many are incentivized
- Oversizing for your space: Too much light wastes electricity
- Ignoring warranty: Reputable brands offer 3-5 year warranties
- Forgetting dimmer value: Dimmable lights grow with you
Don't Forget: Heat Management
LEDs produce less heat than HID, but they still generate warmth. Ensure your tent has proper ventilation. A 4-inch inline fan is sufficient for most small grows. Check out our equipment page for ventilation recommendations.
The Bottom Line
For a first grow in a 2x2 or 2x4 tent, a Mars Hydro TS1000 or Spider Farmer SF1000/2000 is perfect. These lights hit the sweet spot of price, performance, and reliability. Upgrade to premium options once you've got a few grows under your belt and want to maximize efficiency.
Ready to set up your grow space? Our complete growing guide walks you through the entire process from equipment selection to harvest.