Sowing in trays under cover

How to do it

1. 1Fill the tray with seed compost, strike it level and firm it lightly. Seed compost is low in nutrients on purpose — richer compost gives soft, leggy seedlings.
2. 2Sow thinly. The commonest reason seedlings damp off is that they went in at three times a sensible density.
3. 3Cover to about the depth of the seed's own size, and leave fine seed such as Nicotiana, Begonia and Antirrhinum uncovered on the surface.
4. 4Water from below: stand the tray in shallow water until the surface darkens, then lift it out and let it drain.
5. 5Prick out into individual cells as the first true leaves appear, holding each seedling by a leaf and never by the stem.

Plants that use it

Their calendar has a job that points to this guide.