March – Things start in earnest now but don’t be in a hurry to sow early season vegetables if the ground is still wet and cold. This is the main time for sowing broad beans, brussels sprouts, leeks onions parsnips early peas and turnips; also early potatoes and carrots under cloches. Pot on tomatoes and cucumbers in a heated greenhouse.
Start tender fuchsias into growth. Plunge the pots into water and allow to drain then prune hard taking out weak shoots. Once new growth starts replace some of the compost and repot. Sweet peas should be ready to plant out at the end of the month and into April. For exhibition you’ll need to train them singly up canes 2.4m x 30cms (8ft x 12″ins) apart. Tie in the strongest side shoot and remove the others. As the stems grow pinch out all the new side shoots, and all the tendrils and tie in alternate leaves so all the energy goes into the growing stem. Well worth the effort and you’ll get much larger blooms and stems. Sow seeds of hardy perennials such as lupins, delphiniums and pinks. Now is the best time to divide and replant clumps of snowdrops if necessary.
April – Harden off seedlings of plants sown last month eg lettuce, onions and cauliflower. Prick out others as they reach the first true leaf stage. Later in the month sow runner beans, leeks, courgettes, marrows and cucumbers under glass. French beans can also be started off in the greenhouse now but don’t be too hasty to plant out in the garden as they hate cold soil. Make successional sowings of lettuce. Pot on late sowings of tomatoes. Sow outdoors crops of peas, broad beans, cabbage, beetroot , spinach, parsnips. Plant potatoes.
Cover Strawberries with fleece or cloches for an earlier crop. Trim and feed rosemary.
Sow hardy annuals where they are to grow. Plant gladioli corms in groups of 5 or 6. Pinch out the dead heads of daffodils; Feed and mulch roses.Keep the hoe moving to keep weeds down.
May – A busy month ahead especially when the threat of frost is over and plants can be safely put out. Keep an eye on the weather forecast; so long as it is not cold, and plants have been hardened off, the earlier bedding plants such as petunias, begonias, salvias and lobelia etc can go out the better so plan now. Dahlias and hardy chrysanthemums can also go out. Remember to pinch out side shoots and tendrils of sweet peas if you want larger stronger flowers. Tie in alternate leaves and wait for 4 buds on flowering stems and nip out others if you are exhibiting.
Earth up potatoes or cover with newspaper if frost is likely, sow runner beans, marrows, courgettes, peas, French beans, salads, spinach and root crops for winter storing. Grow climbing French beans to gain more space and especially try climbing blue beans, they crop heavily and are delicious. Watch out for blackfly on the broad beans and pinch put the tips once the lowest pods have set to deter infestation. Tie in greenhouse tomatoes and pinch out any side shoots, except on bush varieties ( these will root and usefully make more plants if potted on).
Those with fruit trees can prune plums and cherries this month and pinch out shoots on grapevines. Its also a good time to put out pheromone traps for apple, plum and raspberries fly. Talking of ‘nasties’ keep an eye out for snails and slugs, especially on the lupins, hostas and lettuces and pick them off after dark or use pet and bird friendly pellets ie ones not containing metaldehyde.