Advice
RHS Help & Advice
Sowing tender vegetables
Vegetable plants that require some heat to grow can be sown, from this month on, in the protection of a glasshouse or on a warm, sunny windowsill. The seedlings can eventually be planted outdoors, when the risk of frost and adverse weather has passed
Conditions for germination
Although seeds of tender plants withstand chilling, seedlings generally are sensitive to temperatures below 12°C.
Germination occurs best in temperatures between 18–25°C, with later growing conditions of at least 15°C. If warm and bright conditions cannot be maintained, delay sowing until April when conditions are more favourable.
Crops with small seeds
Small-seeded crops such as tomatoes, peppers and aubergines produce tiny seedlings that grow slowly. The earlier these can be sown, the better. Larger-seeded crops, such as courgettes, cucumbers, melons, squashes and sweet corn, produce large, quick-growing seedlings. These can be sown later, in April or May - otherwise plants may be ready before conditions are suitable outdoors.
Getting started
Use a well-drained medium such as proprietary seed-raising compost or a 50:50 mix of perlite and multi-purpose compost. Sow small seeds on the surface of lightly firmed media, barely covered with vermiculite or sieved compost. Stand the pots in a pan of lukewarm water until the surface darkens, then transfer to a warm environment to germinate. A heated propagator is ideal, but a windowsill in a warm room can be as effective.
Germination and further care
Prick out seedlings into individual pots of multipurpose compost. Sow larger seed singly, or two to a cell tray and discard the weak one.
Grow seedlings in full light and warmth. A sunny windowsill is effective if a glasshouse is not available. Water to keep the roots moist, but avoid sogginess. Start feeding with general-purpose liquid fertiliser from six weeks after pricking out. Peat-free compost is highly suitable for raising vegetable plants but often needs more frequent watering and more generous feeding than peat-based media.
Guy Barter