Easy propagation MAKE EARLY SOWINGS
Start off slow-growing annuals, hardy sweet peas and quick-flowering perennials for a feast of summer colour
You may be itching to start gardening again, but even if your greenhouse is heated, light levels at this time of year are low, which can be a problem for seedlings. It will be another four months before the risk of frost has passed, which is a long time to look after frost-tender plants indoors. However, a handful of slowgrowing annuals can be sown and there are some perennials that, if sown early enough, can put on enough growth in their first year to allow them to flower in late summer.
How to do it
Perennial achilleas can flower in their first year. Sow them in February on the surface of a seed or multipurpose compost in seed trays or modules. They need light to germinate, so don’t cover them. Water and use a propagator lid or plastic bag to retain humidity. Half-hardy snapdragons are slow to emerge. The very fine seeds germinate best when sown thinly on the surface of a tray of seed compost. They also need light, so don’t cover with compost. A heated propagator or warm sunny windowsill will encourage germination. Late-flowering Cobaea scandens won’t produce its blooms until August, so start them now to appreciate them before frost strikes. Sow into individual pots filled with seed compost, place the seed on their sides and cover with a sprinkling of compost or Vermiculite. Place in a heated propagator or seal inside a plastic bag on a sunny windowsill. Hardy sweet peas make long roots, so sow 4-5 seeds into a tall pot, loo roll or newspaper tube filled with multipurpose compost. Place in a cold greenhouse or cold frame and cover with chicken wire until they’ve germinated to protect them from mice. Aftercare: Water small seeds from below so you don’t disturb the compost. Place trays or pots in a dish or sink with a small amount of water. Larger seeds can be watered from above. Remove excess moisture from propagator lids or plastic bags daily to avoid fungal diseases building up.