Aubergines, chillies, and peppers

Towards the end of the month, begin planting out young aubergine, chilli, and pepper plants raised indoors. Harden them off first, and keep them under cloches on cold days and at night if temperatures are still low.

Harden off aubergine seedlings before planting out

Cucumbers

Towards the end of the month when the soil is warm and frosts are over, harden off and then plant out outdoor or “ridge” cucumber seedlings.

A tray of cucumber seedlings ready for planting out

Globe artichokes

This month is your last chance for propagating artichokes by dividing and taking offsets from established plants, and planting them out.

Leeks

May is usually the first month during which you can start transplanting or “dibbing in” young leeks.

A bed of leeks “dibbed in” to deep, narrow holes

Peas

Continue planting out pea seedlings raised indoors or in cold fames. Provide them with supports to which they can cling, and net them to keep off birds.

Rhubarb

Transplant any young rhubarb plants you’ve grown indoors from seed.

Strawberries

Continue planting strawberries. Alpine varieties need to be planted now if you want them to fruit this summer.

Sweet potatoes

If it has been a mild spring, it may be worth planting sweet potato “slips”, burying them in special earthed-up mounds or ridges. Otherwise, wait for warmer weather to arrive next month.

Brussels sprouts, cabbages, and cauliflowers

Unless it’s very cold, start planting out Brussels sprouts, summer, autumn, and red cabbages, and autumn and winter cauliflowers that you’ve either bought from the garden centre or raised indoors from seed. They all grow quite large so space them out generously and don’t crowd them.

Celery

Begin planting celery this month: self-blanching types in closely spaced blocks, and trench varieties in specially prepared celery trenches. Protect from frost if necessary.

Celeriac, Florence fennel, and kohl rabi

Harden off and transplant seedlings raised indoors or growing outside in cold frames.

Courgettes, marrows, pumpkins, and other squashes

Plant out in soil that has been enriched with plenty of organic matter. Keep vulnerable young plants well watered, free of slugs, and protect them with cloches from lethal, late frosts.

Plant out pumpkin seedlings in richly manured soil

Herbs

Transplant container-grown herbs that you’ve either bought or propagated and raised yourself. Tender plants such as basil may still need covering at night.

Lettuces and other salad leaves

Continue transplanting lettuce seedlings. Homemade bottle cloches protect them from both frosts and slugs.

Potatoes

The last of your seed potatoes should go in by the end of the month at the latest.

Sprouting broccoli

Transplant seedlings into specially prepared beds where the soil has been firmly packed down. Like all brassicas, broccoli likes firm ground. Fit brassica collars to prevent female cabbage root flies from laying their eggs.

Sweetcorn

Start planting out any young sweetcorn seedlings you’ve bought or grown indoors or under cover. Sow them in blocks, and if necessary protect them with improvised bottle cloches.

Tomatoes

In May, garden centres and nurseries are full of young tomato plants for sale. But don’t be tempted until next month if there’s still a risk of frost and you’re unable to cover them at night. Home-made bottle cloches may be the answer if you’re too impatient to wait.