Cultivate and prepare seedbeds, covering them with clear polythene or fleece to warm up the soil before sowing.
Chit early and maincrop potatoes. In mild regions, earlies are planted out in the second half of the month. Plant shallots, garlic and onion sets. Plant Jerusalem artichoke tubers.
Plant asparagus crowns. A deep, friable, well-drained soil with plenty of organic matter incorporated is ideal.
Many vegetable crops can be sown this month, especially in mild areas with light soil, including: broad beans, carrots, parsnips, beetroot, bulb onions, lettuces, radish, peas, spinach, summer cabbage, salad leaves, leeks, Swiss chard, kohl rabi, turnip and summer cauliflower. Be guided by the weather, and sow only if conditions are suitable (as per guidance on the seed packets).
Fleece and polythene can be used to protect early outdoor sowings. Many vegetables can bolt if sown outside too early without protection (beetroot being an example). A greenhouse or conservatory is useful in all but the very mildest areas with the lightest soils, to start seeds off - hardening off and transplanting the young plants into the vegetable garden later in the spring.
Sweet peppers, tomatoes, cucumbers, aubergines, celery, salads and globe artichokes can all be sown in a frost-free greenhouse. Artichokes and celery can be transplanted outside later in the spring. Tomatoes can either remain in the greenhouse or be grown outside from early summer onwards. Peppers, cucumbers and aubergines do best kept under cover. Salad crops vary - it is best to check the temperature requirements on the seed packets.
Feed spring cabbages that have been standing all winter. Use high nitrogen feeds such as pelleted poultry manure.
Continue to force chicory and seakale. Dig up selected chicory roots, pot them up, and position them in a dark warm place (10-13°C/50-55°F), with an upturned light-proof pot over them. The tasty chicons will appear in three to six weeks. Seakale is best forced outside at seasonal temperatures, with an upturned pot or cardboard box/tube over the top to exclude the light.
Put supports in place for peas.
Continue to harvest Jerusalem artichokes, parsnips, spring onions, leeks, winter salads, spring cauliflower and cabbage, Brussels sprouts, chicory, rhubarb, kale and sprouting broccoli.
When spring cabbages are ready to harvest, cut them off the stem and make a cross in the top of the cut stem. Sometimes mini-cabbages, or ‘spring greens’ will grow from the cut stems.
Feed crops which have been left sitting over winter (e.g. lettuces and brassicas). A balanced fertiliser such as Growmore or blood, fish and bone would be best, or a high nitrogen choice such as poultry manure. Avoid tomato feeds (which have high potassium levels) for green, leafy crops. There is enough potassium in balanced feeds to keep them going.
You could prepare your runner bean supports and trenches for sowing (in May) or planting out (in June). This will save you time later.
Celery trenches can also be prepared, but for planting very soon (depending on the weather in your area). Plenty of organic matter, traditionally well-rotted manure, is key to improving both water retention and drainage simultaneously, and in helping to ensure the success of the crop.
Try to avoid digging in wet weather, but if gardening on wet soil, work from a plank of wood, to avoid treading on the bed and compacting the soil.
Start regular hoeing, to keep annual weeds under control. Deal with perennial weeds as appropriate, either digging them out or using a weedkiller.
Material courtesy of www.rhs.org.uk