What to Do on Your Allotment in May

May is the month allotment holders wait for all year. The last frost date passes (usually mid-May in most of England and Wales, later in Scotland and higher ground), tender crops can go outside, and the plot transforms from bare soil into a productive growing space almost overnight.

What to sow in May

Direct outdoors (after last frost): - Dwarf french beans and climbing french beans — sow 5cm deep, 15cm apart. They germinate and grow fast. - Runner beans — sow direct at the base of pre-erected canes or poles. - Sweetcorn — sow in blocks (not rows) so wind pollination can occur. Each plant needs neighbours. - Courgettes — can go direct outside now; one plant per square metre minimum. - Pumpkins and winter squash — give them space. They will roam. - Cucumber — outdoors in a sheltered, sunny spot, or in a greenhouse. - Tender herbs — basil, coriander (direct outside), dill.

Continue succession sowing outdoors: - Lettuce, radishes, beetroot, spring onions, chard.

What to harvest in May

• Asparagus — continue cutting until late May/early June when you should stop to let fronds develop for next year.
• Broad beans — if sown in autumn or early spring, the first pods will be ready in late May.
• Spring onions, radishes, salad leaves — from March/April sowings.
• Rhubarb — still producing strongly; stop pulling in early June.

Key jobs for May

Plant out tender crops. After hardening off, plant tomatoes, courgettes, peppers, and other tender crops into the ground or large containers. In the north, wait until the very end of May to be safe. Watch the forecast and be prepared to cover or bring back in if frost threatens.

Pinch out broad bean tips. When plants are in flower and have 4–5 sets of pods forming, pinch out the growing tip at the top. This deters blackfly (which colonise the soft growing tip) and directs energy into filling pods.

Set up support structures. Erect canes, poles, or frames for beans and tomatoes before you need them. It is much harder to do it after plants are established.

Water regularly. Warm, dry May weather means seedlings and young plants need consistent moisture. A deep watering 2–3 times a week is better than daily shallow watering — it encourages roots to go deep.

Pests to watch

• Blackfly colonise broad beans from May. Pinching out the tips and a strong jet of water remove most infestations. Avoid chemical sprays near flowering plants.
• Slugs remain a major threat to seedlings and newly planted crops. Beer traps, copper tape, and ferric phosphate pellets all help.
• Vine weevil — irregular-edged notches on leaves are the telltale sign. Nematodes watered into pots in May are highly effective.

Quick win: plant a few spare courgette plants

Courgettes fail for many reasons — slug damage, cold nights, waterlogged soil. Buy or grow two or three plants and only plant out the best one. Keep the others in pots as insurance for another week or two.