The current weather forecast indicates average temperatures during the day plummeting overnight below zero. So we suggest delay your outdoor sowings until conditions improve. Especially if your soil is heavy clay and takes a while to warm up. A good indicator of readiness is the emergence of weed seedlings. Or cover your seedbeds with clear polythene or horticultural fleece to warm up. Try to avoid cultivating the soil when it’s wet. To avoid treading on and compacting the soil lay a plank down to stand on, alternatively build up raised beds to sow into.
If your ground is ready then it is get set - SOW. Plant onion, shallot and garlic sets, chit your potato varieties, plant Jerusalem artichoke tubers and asparagus crowns. Sow outdoors broad beans, carrots, parsnips, beetroot, spring onions, lettuces, radish, peas, spinach, summer cabbage, salad leaves of all descriptions, leeks, swiss chard, kohl rabi, turnip and summer cauliflower. Sow indoors alpine strawberries, aubergines, celery, cucumbers, globe artichokes, sweet peppers, tomatoes, and salad leaves for cut and come again.
Starting late March through to May begin sowing Hardy Annuals. Try pot marigold, alyssum, chrysanthemum, godetia, candytuft, gypsophilia, sunflower, poached egg, tree mallow, night-scented stocks and nasturtiums. These will withstand cold nights if sown early but may need covering with fleece or newspaper if heavy late frosts are forecast.
Half-hardy annuals such as amaranthus, cosmos, cleome, cobae, nemesia, marigolds and nicotiana. are very sensitive to the cold, so should be sown indoors and planted outside after the last frost. This allows for reliable germination and lets the seedlings grow on strongly in ideal conditions before planting out
quote by- ~Ralph Waldo Emerson