Continue preparing seedbeds for new plantings. Break the soil down to a roughly level surface, so that it can dry out during sunny or windy weather. This will help you to create a fine surface, or tilth, when the seedbed is raked level.
Monitor soil temperature to see how quickly it is warming up. The seeds of many vegetables need temperatures of 5-7°C (40-45°F) in the upper layer of soil before they will germinate.
Warm the soil before sowing or planting by covering areas with cloches, low polythene tunnels or black plastic sheeting. If the weather is dry and windy, remove the covers to allow the soil to dry before sowing
Prepare trenches for planting runner beans, peas, marrows or pumpkins in late spring or early summer.
Dig areas as they become clear of crops and compost the plant waste. Dig in any overwintering green manures.
If the soil is wet, dig trenches 15-20 cm (6-8 in) deep and wide at 1.2 m (4 ft) intervals. This creates mini raised beds in between, with improved drainage.
Order seeds and young vegetable plants for delivery later. Although young plants and seedlings are becoming available now, do not be tempted to buy too early in cold areas unless you can provide them with the protection they may need.
Make early sowings of crops such as beetroot, broad beans, carrot, lettuce, peas, radish, spinach and turnips when soil conditions become suitable. Choose early varieties of these crops where possible.
Sow many of the cabbage family outdoors, including cauliflowers, kale, kohl rabi and sprouting broccoli, all of which mature much later in the year. Choose different varieties to give a continuity of supply: cauliflowers, for example, can be autumn-maturing (early to late autumn), winter-maturing (late winter through to early spring) and spring-maturing (early spring until early summer the next year).
Plant out bulb onions and onion sets.
Plant early potatoes in March and main crop potatoes towards the end of April.
Plant asparagus and globe artichokes.
Sow root vegetables outdoors. Dig down two spade depths to allow deeper root penetration and better quality vegetables.
Sow hardier vegetables outdoors when the soil reaches a minimum temperature of 7-7.5°C (44-45°F).
Begin successional sowings of quick-maturing crops such as lettuce and radish, and crops that you don’t want maturing all at once, such as peas and dwarf beans.
Sow runner beans, which like a warmed soil, later rather than earlier, in double rows. Position supports as soon as the seedlings emerge, as bean seedlings grow rapidly.
Inspect any vegetables that you have stored over winter at regular intervals. Remove any showing signs of mould or rot before they infect their neighbours. Use up quickly those that show signs of growth or withering. Stored crops could include beetroot, carrots, garlic, onions, potatoes, shallots, swedes and turnips.
Plant out autumn and winter-maturing brussels sprouts.
Begin to harden off and plant out hardy crops, such as peas, started off in pots under glass in winter.
Mulch perennial crops, such as rhubarb or artichokes, with well-rotted organic matter. This will help suppress weeds and retain moisture.
Protect seedbeds and seedlings from birds by covering them with fleece or netting, or using bird scarers. Brassicas are particularly vulnerable, and wood pigeons will feed on any cauliflowers they can reach.
Water young plants regularly to ensure they keep growing steadily.
Look out for signs of potential pests, such as slug damage or aphid infestation. Pests are more easily dealt with if spotted early.
Protect the cabbage family from flea beetle and cabbage root fly damage by covering with fleece or fitting ‘collars’ round individual plants.
Harvest asparagus shoots in established beds, once they are about 15 cm (6 in) high. Slice the stem 2-3 cm (1 in) below soil level.
Continue harvesting the flowering shoots of sprouting broccoli varieties so that more are produced.
Start a long-term planting of asparagus (it takes five years to produce spears). Set the crowns in trenches 10 cm (4 in) deep, 30 cm (12 in) apart, with 45 cm (18 in) between the crowns.