If you’re wondering what vegetables you can plant in May then read on…
May is a busy time of year in the allotment or vegetable garden as the soil begins to warm up and temperatures become more consistent.
Brussels sprouts, cabbages, sprouting broccoli, kohl rabi and cauliflowers
If the weather is favourable then now is the time to plant out those brassica plants you’ve grown from seed or bought as seedlings.
You’ll need to get most slow-growing brassicas in quickly (like sprouts) although you can keep planting kohl rabi, sprouting broccoli and calabrese through until July.
Brassicas need to be planted in a different place each year to avoid pests and diseases like club root. (This is called crop rotation.)
They can be returned to the same position after 3 years (in the fourth year).
All brassicas (except spring greens) benefit from added organic material and a natural fertilizer and require a big space with well compacted soil around their roots.
Cucumbers, courgettes, pumpkins, and other squashes
Plants can be planted outside when the risk of late frosts have past and the soil is warmer.
Harden plants off by placing outside for longer periods each day for around 2 weeks before planting.
Add plenty of well rotted manure to beds and protect from slugs. (Slug collars and evening slug patrols work for us.)
Be prepared to protect plants with cloches, fleece and/or straw if the weather turns cold.
Continue transplanting your seedlings and protecting from slugs and snails. Cover young seedlings with bottles cut in half or buy slug collars.
Plant mixed salad leavs, lettuces, spinach, swiss chard and oriental leaves like mizuna.
Maincrop peas, sugar snaps and mangetout
Pea seedlings that have been raised indoors or under cover can be hardened off and planted outside in May.
Use canes, sticks, string or netting to provide support for them to climb.
They’ll also benefit from a net to prevent birds from feasting on new shoots.
French beans and runner beans
Tender crops like these will prefer to be planted out when the weather is consistently warmer.
From late May/early June you can transplant your runner beans and French beans outside.
Succession sow dwarf varieties every three weeks until early summer for a constant supply. Non-dwarf varieties will crop until the end of Summer provided you pick them regularly.
Your sweetcorn seedlings can be sown in blocks when frost risk has past. Protect if weather turns cold.
Chillies, and peppers
Both peppers and chillies will do better in a greenhouse but if planting outdoors you can do so now.
Harden plants off and protect if cold.
Root vegetables like carrots and parsnips prefer to be sown directly in their final growing position. See ‘What Seeds To Sow In May‘ for details.
Your multisown beetroots can now be hardened off and transplanted in their clumps.
If you want to propogate globe artichokes then this month is the cut off.
Transplanting young leeks is called “dibbing in”.
To plant leeks you simply make a hole the same size as your leek seeding (around 15-20cm) using a dibber (ours is the end of an old spade pointed on one end).
Use your dibber to make holes along a row, 15cm apart with 30cm between rows or if planting in a block leave 20cm in each direction.
Drop each leek or multi sown module in a hole and water in (fill with water to the brim don’t press soil in). Let the soil fall back in on its own as the leek expands in size.
May is the time to harden off plants grown under cover and planting them in their final position outdoors.
When planting celery make sure it is hardened off properly before planting as it is liable to bolt and seed if shocked or chilled during transplanting or growth.
You will need to have prepared a bed for your celery by digging a 35-50cm wide by 30cm deep trench in October, November or March and adding well rotted manure.
The celery will be planted in a line along the trench and plants earthed up (mound soil around stems when 30cm tall) in order to blanch stems.
Alternatively choose self blanching celery planted in a block 23cm aparth (9inches) and skip this step.
You’ll need to keep them well watered and never let them dry out.
In May you can transplant any rhubarb plants you’ve grown from seed.
Strawberries can be planted in May and will benefit from a generous amount of well rotted manure.
In May you can transplant container-grown herbs although you’ll still need to protect more tender herbs like basil.
Sow Maincrop potatoes in trenches, under straw or in towers and tubs this month. They’ll be ready in around 20 weeks.
Unless you have a very warm position and live in a mild part of the country then avoid the temptation to plant tomato plants outside until the end of the month.
Even then many varieties will perform better undrr cover especially if you are in a cooler part of the country and have heavy rainful.
Click to download our free printable Gardening Month by Month Gardening Guide.
People who read ‘What To Plant in May’ also read ‘What Seeds To Sow In May‘.