How to Use Grow Lights Without Burning Plants
Grow lights burn plants when too close or too intense. Keep LED lights 2–4 inches above leaves, run 14–16 hours daily, and do the hand test.
The hand test: hold your hand at leaf level. Warm after 30 seconds = too close.
Distance by Light
| Light | Distance |
|---|---|
| LED shop light (20W) | 2-4 inches |
| LED panel (45W) | 6-12 inches |
| T5 fluorescent | 4-6 inches |
| Full-spectrum LED | 12-24 inches |
Signs of Burning
- Bleached white leaves
- Crispy brown edges
- Wilting under light
- Stunted growth
Fix: Raise light 2-4 inches.
Signs of Too Far
- Leggy seedlings
- Pale leaves
- Slow growth
Fix: Lower light.
Common Questions
Can I leave the light on 24 hours? No. Plants need dark periods.
How long per day? 14-16 hours.
What about heat? LEDs run cool. Fluorescents warmer.
Do I need a timer? Yes. Consistent schedule.
What if leaves turn white? Sunscald. Raise light.
Can I use a regular bulb? No. Wrong spectrum.