Indoors on a sunny windowsill or in a heated propagator: chillies, peppers, aubergines, tomatoes, sweet peas, and antirrhinums. Under cover in a cold frame or unheated greenhouse: broad beans, peas, lettuce, hardy annuals like ammi and orlaya. Outdoors only in mild areas with prepared soil: broad beans, parsnips, and the very first early peas towards the end of the month.

In most of the UK, yes. The soil is still too cold and wet for reliable germination, and seeds sown directly will sit and rot rather than sprout. Wait until the soil crumbles between your fingers without sticking together in a wet lump — usually mid to late March. If you cover the soil with cloches or fleece for a fortnight beforehand, you can sometimes get away with a late-February sowing in milder areas.

Chillies and peppers benefit from a January or early February sowing because they need the longest growing season. Tomatoes are best sown mid to late February if you want fruit by July, or early March for a slightly later start. Use a heated propagator or warm spot indoors at around 18–21°C. Without that warmth, wait until late March or early April.

Usually one of three things: soil too cold (the most common cause — check with a soil thermometer if you have one), soil too wet (waterlogged seeds rot rather than sprout), or seeds buried too deep (a covering of two to three times the seed's diameter is plenty). Patience also helps; some February sowings simply take longer to emerge than the same seed would in May.