How to start seeds indoors in January and February?
Starting seeds indoors takes containers with drainage holes, a light seed-starting mix, steady warmth and, above all, plenty of light, ideally artificial. Before transplanting, seedlings need hardening off outdoors, gradually, for about two weeks.
Light
University of Minnesota Extension says tall, spindly seedlings are mainly a sign of too little light. It recommends fluorescent or LED lights a few centimetres above the seedlings for 12–16 hours a day, always leaving a dark period.
Warmth and containers
Give each seedling its own cell so the roots don't tangle. A heat mat under the trays helps germination and reduces damping off. A windowsill is less suitable than it looks: cold at night and liable to overheat by day.
Water and feeding
Keep the mix moist but never waterlogged. Seedlings don't need feeding until they have a few true leaves.
Hardening off
About two weeks before transplanting, start putting seedlings outside for a few hours a day, in shade and out of the wind. Then gradually lengthen their time outdoors and their exposure to sun.
In the app
Every plant in the catalogue has its own sowing calendar, and weather alerts for your area help you judge whether to sow now or hold off.
Frequently asked questions
What should I start indoors in late winter?
Long-season, heat-loving crops such as tomatoes, peppers and aubergines, timed to your area's last frost.
How deep should I sow?
A rule of thumb is about twice the seed's width, but the packet has the final word.