International Dawn Chorus Day is celebrated annually on 3 May.
- Hand weed & hoe kitchen gardens regularly.
- Strawberries: Place straw under plants to keep fruit clean; straw mulch also helps discourage slugs and snails. Feed plants with tomato fertiliser every week or two.
- Keep an eye out for early aphid and other pest attacks like lily beetles & larvae.
- Start earthing-up potatoes when foliage shoots reach 9 inches (23 cm) to prevent green tubers and remove any cold-damaged leaves.
- Remove raspberry suckers encroaching on paths or between rows.
- Broad Beans: Support with string attached to stakes 4 feet (1.2m) apart. Put in supports for pea plants & broad beans.
- Water newly planted trees & shrubs every 4 days (unless there’s prolonged rainfall)
- Thin vegetable seedlings that were direct-sown in April, including beetroot, spring onions and spinach.
- Inspect gooseberry bushes regularly for signs of sawfly damage. Pick off by hand.
- Herbs: pinch out lemon balm and mint to prevent flowering and encourage bushy growth. Successional sowings of tender herbs such as basil can be made in May.
- Frost-tender French and runner beans can be sown indoors individually into 3 inch pots. Plant out early next month.
- Cauliflower, Savoy cabbage, purple sprouting broccoli, kale and calvero nero all need a long growing season. Start seedlings now in small pots and transplant when sturdy with 4 or 5 sets of leaves.
Plant-out tender vegetables — after all risk of frost has passed
- Tomatoes – hold back from planting outdoors too early. Tomatoes suffer if exposed to temperatures below 12 C.
- Courgettes – towards the end of May. Harden off plants under cloches or frames to protect against frosts.
- Pumpkins – towards the end of May
Sow Directly into prepared ground
- Succession sow borage from May to July.
- Succession sow salad crops.
- Succession sow herbs such as basil, coriander, dill & parsley every 10-14 days
- Sow carrots, radishes, beetroot, lettuce and spring onions successionally for continuous cropping
- If weather is favourable in milder regions sow French & runner beans directly into soil in late May.
- Sow cauliflower, sprouting broccoli and leeks for harvesting next winter.
- Sow parsnip now in the position they are to crop to give small roots for winter.
- Rhubarb. Harvest up to half the stems of established rhubarb clumps (don’t take more than half the stalks).
- Start harvesting asparagus from established plants when spears are 5-7 inches tall (13-18cm), cutting 1 inch (2.5 cm) below soil level.
- Harvest early crops of radish & salad leaves as they mature (and continue sowing for succession crops).
Flower / Ornamental Garden
- If daffodil flowering was poor, lift and divide bulbs. Replant larger bulbs in ground improved with organic matter.
- Continue dead-heading spring flowering bulbs. Let foliage die down before cutting it down (or lifting).
- Cut back mildewed pulmonaria leaves for healthy new growth.
- Prune overgrown camelias as they start to put on fresh growth. Cut to young sideshoots which will flower next year.
- Stake, support and tie-in perennials with tall flower stems such as delphinium or plants with heavy, large blooms such as paeonia. Digitalis also like staking.
- Prune spring-flowering clematis such as evergreen clematis montana after flowering (to control growth).
- Prune spring-flowering shrubs such as Forsythia and Philadelphus (mock orange).
- Prune hardy perennials (‘chelsea chop’) – sedums, chrysanthemums, etc
- Look out for lily beetle adults & larvae – early control helps keep populations low.
- Clip evergreen hedges like the pyrocanthus (but check for nesting birds first)
- Tie-in wayward sweet pea shoots to supports.
- Finish planting summer bulbs.
- Tender summer bedding should be thoroughly hardened off before planting. A cold frame open during the day and closed at night, is ideal.
- Plant out tender exotics such as cannas and dahlias (after all risk of frost has passed). Make sure you apply slug & snail controls to dahlias as they put on new growth.
- A sowing of Cosmos in late May will give you blooms from August onwards.
- Thin direct-sown hardy annuals.
- Tie-in sweet peas to their supports.
- Detach baby rosettes from succulents such as echeveria and pot into small containers of gritty compost.
- Take softwood cuttings of hardy and tender perennials like fucschias and verbena.
- May is the start of moth-flight season for many UK species. Night-scented plants (honeysuckle, jasmine, evening primrose etc) attract moths, which in turn attract bats.