Let the old "official" definition of the month be a warning - this month is the last of winter.
As your own sap rises, it is easy to rush ahead and start sowing, but your seedlings are likely to struggle when the weather turns cold and wet again. The air temperature is not so important as that of the soil - hence the traditional test, which involves dropping your pants and sitting your bare bottom on the soil. If you don't feel the cold, the soil is warm enough to sow.
Unwilling to risk embarrassment or arrest? Have patience and wait to sow in April!
Some hardy plants that have survived through the winter will be ready to put on a spurt now; cutting back your chard plants will encourage a burst of fresh new leaves, and spring cabbage will benefit from a good feed.
General Tasks
» Prepare your vegetable beds - fork in over-wintered green manures, and mulches of manure/compost.
Potato/Tomato family (Solanums)
» Plant first early potatoes (in week 4?).
» Sow Tomatoes inside (also in week 4?).
Bean/Pea family (Legumes)
» Sow early peas and broad beans.
Brassica family
» Prepare seed beds for brassicas; sow and cover with fleece.
» Sow swede and turnip in final beds.
» Thin spring cabbages and use as spring greens.
» Harvesting - Broccoli (Winter Sprouting), Cabbages (Spring Greens), Kale, Turnip tops.
Root vegetables
» Sow carrots and parsnip.
» Harvesting - lift last of parsnips before they regrow.
Onion family (Alliums)
» Sow spring onions.
» Garlic can be planted now.
» Leeks taking up space can be lifted and heeled into an odd spot.
» Harvesting - Leeks.
Other vegetable families
» Harvesting - Winter Spinach, Chard.
Herbs
» Take heel cuttings; grow on in pots of compost.
» Some herbs can be sown now direct - but sow Basil inside or under cover.
» Divide large clumps of mint, lemon balm, chives, sage.
Fruit
» Prune autumn-fruiting raspberries.