Best Grow Lights for Seedlings and Clones
Seedlings and cuttings don't want much light — 150–300 PPFD is the whole target, and going brighter is the most common way people kill clones. What they want is gentle, even light close to the canopy, which is why T5 fluorescents and low-wattage LED strips still dominate propagation. Everything below sits in that range, runs cool enough to sit inches above a dome, and is in stock. Pair with a propagation / cloning setup.
How to choose a propagation light
- Target 150–300 PPFD. Un-rooted cuttings have no roots to move water — high light just dehydrates them.
- Even, close coverage beats intensity. A 4 ft T5 sitting 6" above a tray is better than a powerful panel 3 ft up.
- Low heat. The light sits inches from a humidity dome. Anything that runs hot cooks the clones.
- Full spectrum or 6400K blue. Blue-weighted light keeps seedlings compact instead of stretchy.
- 18–24 hr photoperiod is standard for propagation.
Clone room conditions
| Variable | Target |
|---|---|
| PPFD | 150–300 µmol/m²/s |
| Photoperiod | 18–24 h |
| Temperature | 75–80°F |
| Humidity | 70–90% (drop 10%/day after roots appear) |
| Root zone temp | 72–78°F |
What to skip
- Running your flowering fixture at 10% over a clone tray. It works, but the spread is wrong and you'll get uneven rooting.
- Anything that can't hang 6–12" above a tray safely.
FAQ
How much light do seedlings need?
150–300 PPFD on an 18-hour photoperiod. More causes stunting and bleaching before roots establish.
T5 or LED for clones?
LED strips are more efficient and cooler; T5 is cheaper up front and very forgiving on spread. Both work — this is one of the few decisions where the cheap option is genuinely fine.
How close should the light be?
6–12" for T5, 12–18" for low-wattage LED. Watch for stretching (too far) or bleaching (too close).
Related collections
Cloning & Rooting · Best LED Grow Lights for 2x4 & 2x2 Tents · LED Grow Lights
