Propagation Grow Lights

Why propagation lights are different

Every other grow light is chosen for power. A propagation light is chosen for the opposite reason. A seedling or a fresh cutting has little or no root system, so it cannot take up the water and nutrient that fast top growth demands. Drive it hard with a flowering-strength fixture and you get a tall, thin, soft plant that collapses the moment it is transplanted.

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

What to look for

Wattage under 100W covers almost all propagation. The 18W and 26W bars suit a single tray; 40W to 60W suits a shelf; 90W and above is for a full propagation bench rather than a dome.

A long, thin form factor beats a square panel here. Trays are rectangular, and a bar spreads light evenly along one without a hot centre. Most fixtures on this page are bars for that reason.

Low heat lets you hang the light close, which keeps seedlings compact instead of stretching toward a distant source. This is where LED clearly beats the older T5 and CFL approach, though T5 units remain popular and are still stocked here.

Light schedule for propagation

Cuttings and seedlings are usually run on a long day — commonly 18 hours on, 6 off — using a timer rather than doing it manually. Pair the light with a propagation kit for the tray, dome and medium, and a heat mat if the room is cool — root-zone warmth does more for strike rate than extra light ever will.