Summer bedding can be planted out towards the end of the month. But keep some fleece ready to cover it if frosts are forecast. Plant summer tubs and hanging baskets.
Move Daffodils from pots that have finished flowering out into the garden to die back naturally. Feed with a liquid fertilizer to get a good display next year.
Harden off Dahlias, Cannas and other tender exotics, ready to plant out.
Thin out hardy annuals sown last month to encourage bushy plants.
Trim back spreading plants such as aubretia and alyssum after they have flowered, to encourage fresh new growth.
Pull up forget-me-nots when they finish flowering to prevent them becoming a weed.
Prune out overcrowded and dead stems of early-flowering clematis such as C. alpina after flowering. Carry on tying in climbing roses and sweet peas.
Prune early spring flowering shrubs after flowering.
Cut back late summer flowering plants such as Penstemons and Salvias now for a good display later in the year. Trim Lavenders.
Spray against Black Spot on roses when you see the first signs. Healthy plants are less likely to succumb, so keep them watered and fed.
Earth up potatoes as they grow for heavier crops, and to protect them against late frosts.
Continue harvesting Asparagus spears before they reach 20cm to keep the crop coming. Pull radishes when they are ready, and keep them watered they soon become woody.
Carry on sowing seeds directly into the ground; they should germinate quickly now the soil has warmed up. Thin out directly sown seedlings.
Harden off tomatoes, squashes and courgettes ready to plant outside next month.
Pinch out Broad bean tips when the first beans start to develop; this prevents blackfly becoming a problem. The tips can be lightly cooked as a vegetable.
Keep weeds under control, particularly around seedlings, and onions and garlic, which don’t like competition.
Put up runner bean poles and sow runner beans in pots ready to plant out next month.
Place straw under developing strawberries to keep them off the soil and protect them from slugs.
Harvest Rhubarb; only take a few sticks from each plant at a time to allow it to keep growing.
Hang pheromone traps in apple trees for controlling codling moth, and in plum trees for plum fruit moth.
Water young fruit trees well to keep them growing actively, and pinch off the flower buds in their first year to reserve their energy for growth.
Check gooseberry plants for sawfly caterpillars and remove immediately; they can strip a plant of leaves overnight.
Net soft fruit plants and cherries before they ripen. The birds like them even more than we do.
Remember to open greenhouse and polytunnel vents and doors every day; they soon heat up when the sun comes out. Damp down the paths regularly on hot days, this helps to deter red spider mite from taking hold.
Water plants regularly; especially if they are in containers. Plants are growing vigorously now, and use up more water than will be provided by rain. Water early in the morning or evening to reduce water loss.
Any plants in containers should have the top layer of compost removed and replaced with fresh compost and slow release fertilizer. When planting new containers remember to mix in water control gel, and slow release fertilizer to keep the plants growing all summer.
Protect against slugs and snails, they can wipe out a row of seedlings over night, and can cause serious damage to the young growth on herbaceous perennials. Regularly check plants for pests and diseases, it is easier to prevent spread if they are caught early. Hang yellow sticky traps in the greenhouse to monitor levels of whitefly, thrips and other pests.
Weed regularly as they will compete with plants for water and nutrients.
Clip evergreen hedges now. If they have large leaves, such as Laurel, it is best to prune them to shape with secateurs, as shears will cause ugly brown die back on the leaves.
