Harden off and plant out seedlings

Gradually acclimatize tender young plants raised indoors to conditions outside. Move them outside during the day and back inside again at night. Or, if they’re in cold frames or cloches, open them during the day and close them at night. Plant them out only when there’s no longer any danger of frost.

Water seeds and seedlings

Water regularly and generously. May can be a surprisingly dry month, and all growing plants need to be kept moist, especially young ones. They may not survive if you let them dry out.

Watering newly planted sweet peppers

Weed regularly

Keeping on top of weeds is a constant challenge. They will be growing as vigorously as anything else on your plot this month. It’s important to remove them, however, as they compete with your own plants for water and nutrients in the soil. Using a hoe is the least backbreaking way of weeding, and is best done on dry, warm, days when the sun will dry out and kill uprooted weeds.

Protect plants against frosts

There’s always a possibility of late frosts in May. If you decide to take a risk and plant out tender plants regardless, it’s wise to have cloches, tunnels, fleece, or even newspapers on hand to cover them at night if the weather worsens and they look as if they may be in danger.

A plastic bell cloche will protect this cape gooseberry from night frosts

Pot on growing plants

Re-pot into larger containers any plants that are becoming pot-bound if you’re not yet ready to transplant them outside into the ground.

Remove unwanted raspberry canes

Raspberries tend to be over-eager in throwing out new shoots and suckers. Pull or cut some of them out, or you’ll end up with a thicket of canes too dense for sunshine and air to penetrate, and your fruit may be either under-developed or diseased.

Thin gooseberries

Begin to thin out gooseberries as the fruits develop. Any you pick are unlikely to be ripe enough to eat raw but can be used for cooking.

Prune trained fruit trees

Prune trained cherry and plum trees, shorten leaders and side shoots on trained apples and pears, and either thin out or tie in new shoots on trained apricots, peaches, and nectarines.

Thin out seedlings

Seeds you sowed last month may by now have produced seedlings that need thinning. If you don’t thin them, crops such as carrots, parsnips, beetroots, and lettuces may not have room to grow to a reasonable size. Don’t throw away the thinnings – add them to green salads.

Thin carrot seedlings so that the roots have room to swell and grow

Earth up potatoes

Continue regularly drawing soil up around developing potato plants in order to prevent the tubers breaking through the surface. If they are exposed to light, they turn green and can become poisonous.

Put up supports for peas and climbing beans

Peas need hazel or birch peasticks or supports constructed from chicken wire or plastic mesh up which to climb, otherwise they’ll sprawl on the ground and be eaten by slugs and snails. And climbing beans also need supporting canes. It’s worth erecting them now, even if you have not yet sown seeds or planted seedlings.

Support broad beans

Stake broad beans with canes and lengths of string to help them support the increasing weight as pods start to form.

Broad beans supported with canes and string

Feed and mulch globe artichokes

Remove any old straw or bracken that you used as a protective covering for plants during the winter, and either water them with a high- potash feed or spread a rich organic mulch around them.

Cover strawberries and remove runners

If it’s still cold, keep cloches in place over strawberry plants so that they flower and produce a crop as early as possible. Remove the cloches during the day to allow insects to pollinate them. Cut off any unwanted runners.

Pick flowers off new strawberries

Continue to remove all blossom from new summer-fruiting strawberry plants. You don’t want them to crop in their first year.

Weed and mulch fruit bushes

Weed carefully around fruit bushes and canes. After a spell of rain, when the soil is damp, spread a layer of organic mulch over the surface to help retain moisture and suppress the growth of further weeds.