Propagation Grow Lights

Why a propagation light is different

Most grow lights are bought for punch. A propagation light is bought because it holds back. Seedlings and fresh cuttings have little or no root system, so they cannot take up the water and nutrient that rapid top growth would need. Push them with a flowering-strength fixture and you end up with a tall, thin, soft plant that folds the moment it is transplanted.

What this stage wants is steady, even, gentle light — enough to keep growth compact and green while the roots do the real work underground.

What to look for

Wattage under 100W covers almost all propagation. An 18W or 26W bar is enough for one tray; 40W to 60W covers a shelf; 90W and above belongs on a full propagation bench rather than a dome.

A long, thin form factor beats a square panel on this page. Trays are rectangular, so a bar throws even light along the length without a hot spot in the middle. That is why most of the fixtures here are bars.

Low heat means you can hang the light close, which keeps seedlings compact instead of reaching toward a distant source. LED clearly wins this against the older T5 and CFL approach, though T5 units are still popular and we still stock them.

Light schedule for propagation

Run cuttings and seedlings on a long day — 18 hours on and 6 off is the usual split — and put that on a timer instead of switching it yourself. Pair the light with a propagation kit for the tray, dome and medium, and, if the room is cool, a heat mat: warmth at the root zone lifts strike rate more than extra light ever will.