Jobs to do in May

After all risk of frost has passed, plant out tomatoes, courgettes and pumpkins that were sown under cover. Other young plants can be planted out once conditions are suitable, and once they’

Sowing and planting

Fruit

• Plant out alpine strawberry seedlings sown in early spring.

• Sow melon seeds indoors, ideally in a heated propagator. Sow into small pots of peat-free compost. 

Vegetables

• Sow French beans, runner beans, squash, cucumbers and pumpkin seeds directly into prepared beds outside. Be alert to late frosts, and if necessary cover tender seedlings with cloches or biodegradable or re-used old fleece.

• Sow sweetcorn outside in a grid rather than a row to improve pollination. Sow two seeds per hole and, if both germinate, remove the smaller, weaker seedling.
•  Sow cauliflowers and purple sprouting broccoli for harvesting next winter.

• Try sowing some unusual vegetables such as kohlrabi, scorzonera and salsify.

• Witloof chicory can be sown this month, to have some ready for forcing next winter. Sow in drills directly outside.

• After all risk of frost has passed, plant out tomatoes, courgettes and pumpkins that were previously sown under cover.

• Other young plants can be planted out once conditions are suitable, and once they’ve been hardened off (acclimatised to the colder outdoor conditions) for 10 to 14 days.

• Brussels sprouts for next winter should now be ready for transplanting after early or mid-spring sowing.

• Plant out globe artichokes that were previously sown under cover.

• Self-blanching celery can also be planted out towards the end of the month.

• Ridge cucumbers can be sown indoors now, for planting out in early June.

Pruning and training

Fruit

• Remove wayward shoots on fan-trained trees and tie in better placed ones.

• Thin out overcrowded clumps of autumn-fruiting raspberries if necessary, removing weaker stems so the remainder are about 10cm (4in) apart.

• Tie in leading and sideshoots of kiwifruit.

Prevention

• Keep an eye out for asparagus beetles, and pick them off by hand.

• Watch for the small holes flea beetles make on brassica seedlings. Water plants well to help them continue growing despite the damage.

• Protect carrots with insect-proof mesh to prevent carrot fly.

• Consider protecting vulnerable seedlings from slugs by using methods such as hand removal, traps, biological controls and encouraging natural predators.

• Protect brassicas and peas from pigeons. Ensure any netting used is taut and fastened securely so birds and other wildlife don’t get entangled in it. 

• Pick yellowing leaves off brassicas promptly, to prevent spread of grey mould and brassica downy mildew.

• Put up codling moth traps in apple trees.

• Put bird protection in place for vulnerable soft fruit where necessary, ensuring it is securely fitted.

• Remove weeds that risk smothering young plants by hand or by hoeing, and continue through to summer.

General care

Fruit

• Pull off suckers appearing around the base of fruit trees.

• Start regular feeding of fruit trees in pots for the growing season (April to September) using an organic liquid fertiliser.

• Take softwood cuttings of kiwifruit.

• Move growing-bags into the greenhouse to warm up two weeks before planting indoor melons, and water well before planting.

• Gently run your hand over indoor grape vine flowers to pollinate them.

• Make sure fruit isn’t drought stressed, especially those in containers, against a wall or newly planted. Ideally, water with collected rainwater.

• Make sure bees can access caged and cloched fruit flowers to ensure pollination.

• Keep a check on late frost forecasts and protect blossom as necessary.

Vegetables

• Earth up potatoes when the shoots are about 23cm (9in) high, in order to prevent the new tubers going green. Earthing-up is the drawing up of soil around the stems of the plants, leaving just 5–10cm (2–4in) of shoot uncovered so that the plant has enough foliage to continue growing.

• Start to remove sideshoots from cordon tomatoes as you see them. The sideshoots develop in the leaf axils (i.e. between the stem and leaf), and if allowed to develop will sap the energy of the plant and reduce the quality of the yield.

• Support broad beans as stems are likely to flop as pods develop. Insert stakes at the end of rows and at 1.2m (4ft) intervals, then run string around the outside to hold the plants up. 

• Peas need staking with pea sticks, netting, or pruned twigs from the garden.