At last the weather is improving after all the rain and heavy winds we have had.  Spring should be here by now, the ground should be warming up and there is plenty to do in the garden. Keep that fleece handy though as a cold snap can still catch us out. There is lots of sowing, planting and propagating to do, so get out there and start by dividing clumps of any herbaceous perennials that you want to propagate, those that have become too large for their allotted space, and those that are flowering poorly.  Give them adequate water to enable them to settle into their new position.   If you haven’t already done it many shrubs will benefit from a trim this month to encourage new growth. Prune flowering shrubs like forsythia and flowering current etc after they have finished flowering.  
Remove faded flowers from daffodils and tulips, deadhead pansies, primulas and other spring bedding plants when they have gone over.  Divide any congested clumps of snowdrops.
Sow half-hardy bedding plants in trays in the greenhouse or on windowsills, watering regularly and feeding weekly.  Sow hardy annuals in vacant spaces in the garden. Pot up over wintered cuttings of geraniums, fuchsias, etc.  
Weed, dig and mulch established borders.  Plant out autumn sown sweet peas.  Plant out lily of the valley crowns and gladiolus corms.  Fork fertilizer around established bushes and border perennials.  Plant new perennials and protect susceptible plants, especially hostas, from slugs. Plant out Dahlia tubers at the end of the month or start them into growth earlier in the greenhouse.
Remove the top 2-3 inches of old compost from the top of tubs and refresh with new compost. Check to see if plants in tubs are pot bound.  Tip them out and inspect to see if they are or if there is another problem.   Watch out for slugs and vine weevil.  
Dig around established strawberry plants removing all weeds.  Plant new strawberries, pollinate outdoor peaches, nectarines and apricots by hand.  Lightly hoe around fruit bushes and fruit trees and sprinkle in some fertilizer forking it well in.  Spray gooseberries with a systemic fungicide to eliminate mildew.  Start vines into growth in unheated greenhouse.
Sow outdoors broad beans, beetroot, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, kale, kohlrabi, leeks, lettuce, onions, parsnips, peas, radish, rocket, spinach, swede, chard and turnips.  Plant early, second early and main crop potatoes.  Prepare trenches for celery and runner beans.  Plant onion sets.  Plant asparagus crowns.  Harden off vegetables raised in the greenhouse.  Earth up early potatoes to protect the growing shoots.
Plant in a heated greenhouse tomatoes, aubergines, peppers, cucumbers and melons and sow seeds of these for growing in an unheated greenhouse.  Sow French beans to provide an early crop under glass.  Sow marrows and courgettes for planting out in late spring.
Give established lawns their first feed and deal with moss.  Returf or reseed bare patches. Prepare the ground for new lawns, sowing seed or laying turf.