Divide clumps of chives to encourage strong growth. Outdoor sowings Crops to sow outdoors or under cloches include broad beans, beetroots, Brussels sprouts, summer cabbages, leeks, lettuces, hardy peas and radishes. When the conditions have warmed up in late March, onion sets can be planted out into a firm seedbed . Many varieties can be grown outside in summer, with some even thriving in patio pots or hanging baskets. The earliest crops will develop on plants grown under glass, ideally in a heated greenhouse, but an unheated one will do.
Tomatoes are easy to grow from seed, so start sowing now to raise indoor varieties.
Sow in a heated propagator to encourage quick germination , or grow on a windowsill. To raise outdoor varieties, sow later in March, potting on as plants grow. Plant them out in early June. Sowings can be made in April, but plants will flower and fruit far later than those that were sown earlier. Sow tomatoes now, pricking out when big enough to handle.