May is the month every European vegetable gardener has been waiting for. The last frosts have passed in most regions, the soil has warmed enough for heat-loving crops, and beds that looked empty in March are suddenly bursting with seedlings begging to be planted out. Knowing what to plant in May is mostly about timing — moving warm-weather transplants outside, succession-sowing cool-season crops before summer heat arrives, and getting one more round of seeds in for late summer and autumn harvests.

This guide walks through the key planting jobs for May across European climate zones, the tasks that protect everything you have already invested in, and the small mistakes that quietly cost beginners half their May garden every year.

A Quick Climate Check Before You Sow

Before you transplant anything tender outdoors, check where your region actually sits in the European climate map. Atlantic Cfb gardens (UK, Ireland, Netherlands, northern France) generally see safe nights from mid-May. Continental Dfb zones (Germany, Czechia, Poland, Slovakia, eastern France) traditionally wait for the Ice Saints (around 11–15 May) before planting tender crops. Mediterranean Csa zones (southern Spain, southern Italy, southern France) are already in full summer-planting mode and may even be sowing autumn crops by late May.

If you are not sure where your garden falls, our European climate zones guide explains how to find your zone and what it means for timing. A late frost in mid-May will kill a tomato in one night, so this check is worth five minutes.

Direct-Sow Crops in May

Once soil temperatures hold above 10–12 °C, you can sow these directly into prepared beds:

Crop	Sowing depth	Zone notes
French beans (bush and climbing)	4 cm	Dfb: after mid-May. Cfb: early May under fleece. Csa: April onwards.
Runner beans	5 cm	Wait until soil is reliably > 12 °C.
Sweetcorn	3 cm	Sow in blocks of 4×4 for pollination, not single rows.
Courgette and squash	3 cm	One seed per station, spaced 1 m apart.
Cucumber (outdoor varieties)	2 cm	Dfb: late May. Cfb: mid-May with cloche.
Carrots	1 cm	Sow thinly. Cover with fleece against carrot fly.
Beetroot	2 cm	Bolt-resistant varieties for early sowings.
Lettuce, rocket, mixed leaves	0.5 cm	Sow every 14 days for continuous harvest.
Radishes	1 cm	Ready in 4 weeks. Use between slower rows.
Swiss chard	2 cm	Heat-tolerant, harvests into autumn.

Transplant Warm-Weather Crops Outside Now

This is the big May job in most of Europe. The crops you started indoors in February and March are ready to go outside — but only once nights stay reliably above 8–10 °C.

Tomatoes — plant deep, burying the stem up to the first true leaves. Stake or cage immediately. For variety and spacing tips, see our guide to growing tomatoes in Europe.
Peppers and chillies — the most heat-sensitive crop in the garden. In Dfb zones, wait until the last week of May or use a fleece tunnel. Spacing 40 cm.
Cucumbers — outdoor varieties go out from mid-May with some wind protection. Train up a trellis to save space and keep fruit clean.
Courgette and squash — one plant produces a huge amount. Two courgette plants is enough for most families.
Aubergines — only in the warmest, sunniest spot you have. Black mulch helps trap heat.
Basil — extremely cold-sensitive. Hold off until late May in continental zones, even if tomatoes are already out.

Harden Off First

Plants raised on a windowsill or in a greenhouse have not seen real sun or wind. Move them outside during the day for 7–10 days before planting out, starting in a sheltered spot. Skipping this step is the most common cause of stunted, sun-scorched transplants in May.

Succession-Sow These in May

The crops you sowed in March are coming to harvest. May is the month to start the next wave so your garden does not go through a feast-and-famine cycle.

Carrots — sow every 3–4 weeks until early July for a continuous supply.
Lettuce and salad leaves — sow small amounts every 10–14 days. Switch to heat-tolerant varieties (Lollo, Salanova, oak-leaf) as temperatures climb.
Radishes — sow tiny batches every 2 weeks. They go woody fast in heat.
Beetroot — sow a second round mid-May for autumn storage roots.
Spring onions — sow thinly in rows; they take about 8 weeks to reach pencil thickness.
Dill, coriander, parsley — direct sow for fresh kitchen herbs all summer. Our succession planting guide goes deeper into spacing intervals.

Start Indoors for Late Summer and Autumn

May is also the secret month for the autumn garden. While everyone else is busy planting summer crops, get these on the windowsill or in a propagator now:

Brassicas for autumn — purple sprouting broccoli, autumn cabbage, winter cauliflower, kale. Sow into modules in May, transplant in June or July.
Leeks — sow thinly in trays now for transplanting in July. They will harvest from October through March.
Florence fennel — bolt-resistant varieties from mid-May for autumn bulbs.
Chicory and radicchio — start now for autumn and winter harvests.

May Garden Tasks Beyond Sowing

Sowing is only half the job in May. The tasks that protect what you have already planted matter just as much.

Mulch everything you can. A 5 cm layer of straw, compost, or leaf mould around transplants keeps soil moisture stable, suppresses weeds, and reduces watering by half. See how to mulch your garden for materials and depths.
Water deeply, less often. Young transplants need long, slow soaks at the base — not a daily sprinkle on the leaves. Morning is better than evening to limit slug damage. Our vegetable watering guide covers exact volumes per crop.
Stake tomatoes the day you plant them. Driving a stake in three weeks later means damaged roots and a sprawling plant.
Watch for slugs. Mild, damp May nights are slug paradise, and they will demolish young transplants in a single night. Beer traps, copper rings, or simply hand-picking after dusk all work.
Companion plant where you can. Basil with tomatoes, nasturtiums with squash, marigolds at bed edges. See our companion planting guide for tested pairings.
Pinch out sideshoots on cordon tomatoes as soon as they appear, so the plant focuses energy on fruit.

Common May Mistakes

Planting tomatoes too early. A May frost will kill an unhardened tomato in one night. Wait, or be ready with fleece.
Sowing everything at once. May is exciting, but if you sow all your lettuce in week one, you will have a lettuce avalanche followed by nothing.
Forgetting to thin seedlings. Carrots and beetroot that you do not thin produce nothing usable. Be ruthless at the 2-true-leaf stage.
Watering little and often. Surface watering trains shallow roots that collapse in the first hot week. Soak deeply 2–3 times a week instead.
Ignoring slugs until it is too late. By the time you see damage, the population is established. Set traps the day you transplant.

Plan Your May Garden With Plantory

May is the month when the garden plan you made over winter actually meets reality — and it is easy to lose track of what you have sown where, when each transplant went out, and which succession sowing is due next. With Plantory, you can build your May calendar, set reminders for every crop, and keep your sowing log and bed map in one place so nothing slips through the cracks during the busiest month of the year.

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