May is without doubt the most intense and rewarding month in the vegetable garden. This is the great appointment of the season: plants started indoors since February and March finally find their place in the ground, direct sowings multiply, and the garden takes on a whole new dimension. But May also requires vigilance, because the famous Ice Saints — Mamertus, Pancras and Servatius, on May 11, 12 and 13 — can still bring surprise frosts in most regions. The strategy for the month can be summed up like this: before May 13, prepare and protect; after May 13, plant and flourish. This complete guide walks you through every task in May.

The Ice Saints: May's golden rule

The Ice Saints refer to three days — May 11, 12 and 13 — traditionally associated with a risk of late frosts across much of France and central Europe. This popular tradition is grounded in meteorological reality: cold Arctic air can still sweep in until mid-May, causing overnight temperatures to drop to zero or below, even after warm spring days.

For the vegetable gardener, the Ice Saints mark a practical boundary. Before May 13, do not plant tender species outdoors — tomatoes, peppers, aubergines, courgettes, cucumbers, melons, basil. After May 13, in most temperate regions, the frost risk is over and the great planting season can truly begin. This rule applies primarily to temperate climates (Paris basin, Loire valley, Atlantic coast, Burgundy). In Mediterranean regions the boundary falls earlier (late April); in mountain or severe continental zones, it is safer to wait until May 20.

What if frost is forecast after the Ice Saints?

The Ice Saints are a precautionary rule, not an absolute guarantee. If frost is forecast after May 13, protect your plants with a horticultural fleece stretched over hoops. An overnight cover is usually enough — remove it in the morning so plants don't overheat during the day. In case of an unexpected hard frost, plastic bottles filled with water and left in the sun during the day placed near plants can release a little warmth overnight.

Planting tender crops after May 13

The second half of May is the great planting window. All those plants nurtured indoors for weeks have been waiting for this moment. Here is how to install each species in the best conditions.

Tomatoes

Planting tomatoes in the ground is the central event of May. Wait until your plants are 20 to 30 cm tall with at least 4 to 5 well-developed leaves. Dig deep holes (30 to 40 cm) and enrich them with a generous handful of mature compost. Plant deeply: bury the stem up to the first lower leaves, or even higher if the plant is long and leggy — tomatoes produce roots all along the buried stem. Space indeterminate (cordon) varieties 60 to 80 cm apart, determinate (bush) varieties 50 cm apart. Install stakes at planting time to avoid damaging roots later. Water generously and mulch immediately.

Peppers and chillies

Peppers and chillies need even more warmth than tomatoes. Do not plant them until nights are consistently mild (above 12°C). Choose the warmest, sunniest spot in the garden, ideally against a south-facing wall that reflects heat. Plant 40 to 50 cm apart in well-enriched soil. In cooler regions, keep a light fleece available for the first few weeks.

Aubergines

Aubergines are the most cold-sensitive of the solanaceae family. Plant them outdoors only in regions with a long, hot summer. Elsewhere, growing in a large pot (30 litres minimum) on a sunny terrace or in a greenhouse gives more reliable results. Space 60 cm apart in light, warm, fertile soil. Dark mulch (black plastic film) warms the soil and speeds their development.

Courgettes and squash

Courgettes are among the easiest crops to succeed with in May. Plants started indoors in April are now ready (4 to 6 leaves). Plant them in very compost-rich soil, on a slightly raised mound to improve drainage and warming. Space courgettes 80 cm to 1 metre apart, winter squash and pumpkins 1.5 to 2 metres apart — these plants need room. Water at the base, never on the leaves, to prevent powdery mildew.

Cucumbers and gherkins

Cucumbers love warmth and develop rapidly once well established. Plant after the Ice Saints, ideally against a trellis or netting so they can climb. Space 40 to 50 cm on the row, rows 1 metre apart. Water regularly: a cucumber stressed for water turns bitter. In cooler regions, growing under a low tunnel gives excellent results.

Melons (warm regions)

Melons are demanding: they need a long, hot season to ripen properly. In Mediterranean areas and warm continental zones, plant melons in May in the warmest, sunniest corner of the garden. In cooler regions, grow under a tunnel or choose varieties that need less heat. Space plants 80 cm to 1 metre apart.

Transplanting young vegetable seedlings in May

Direct sowings in May

Alongside transplanting indoor-raised plants, May allows a wealth of direct sowings outdoors. The soil is warm, days are long, and germination is fast.

French beans and climbing beans

Beans are the stars of May sowings. They germinate within days in soil at 15°C minimum and produce abundantly. Sow in clusters of 4 to 5 seeds every 30 to 40 cm for dwarf varieties, every 50 cm for climbing varieties. Provide 2-metre canes or stakes for climbers. Stagger sowings every two to three weeks from May to July for continuous harvests through September.

Sweetcorn

Sweetcorn is sown directly outdoors in May, in groups of 3 to 4 seeds every 40 cm, in rows 80 cm apart. Sweetcorn is wind-pollinated: always sow in blocks of at least 4 parallel rows for good pollination. Without this, cobs will be poorly formed. Choose F1 hybrid varieties for guaranteed sweetness: Earlibird, Incredible, or Double Red.

Courgettes and squash (direct sowing)

If you did not start courgettes indoors, you can sow them directly outdoors in May in warm regions. Place 2 to 3 seeds per station, on their sides (to prevent rotting), and keep only the strongest seedling after germination. Germination is rapid (5 to 8 days) when the soil is warm. In cooler regions, cover the sowings with fleece or a cloche for the first few weeks.

Carrots and radishes (successive sowings)

Carrots sown in May will give roots for autumn. Sow in fine rows, 1 cm deep, in loose, stone-free soil. Water regularly to keep the soil surface moist until germination. Radishes are as speedy as ever: sow every two weeks to never run out of crunchy snacks. In the rising May heat, radishes can bolt quickly — choose bolt-resistant varieties like Cherry Belle or National.

Beetroot

May is excellent for beetroot: the soil is warm and germination is fast. Sow in rows 30 cm apart, 2 cm deep. Thin to 10 to 15 cm after germination. Sown in May, beetroot has time to develop perfectly before the summer heat peaks.

Lettuces and rocket

Keep up successive lettuce sowings every two to three weeks. In May, favour heat-tolerant, bolt-resistant varieties such as Batavia Reine des Glaces, Lolla Rossa or Mâche Coquille de Louviers. Rocket also bolts easily in the heat — sow it in a lightly shaded spot to slow its flowering.

Shelling beans and broad beans

Shelling beans (flageolets, borlotti) are sown in May just like French beans. Broad beans sown late in May may still give a small harvest in regions with a moderate summer, but this crop is better sown in autumn or winter in mild areas.

Soil thermometer: the essential May tool

In May, soil temperature varies greatly depending on the time of day and aspect. Take your reading in late morning, at 10 cm depth. Beans: minimum 15°C. Corn, courgettes: minimum 15 to 18°C. Cucumbers, melons: minimum 18 to 20°C. If the soil is still too cold, cover it with black plastic film for a few days to speed up warming.

Indoor sowings still possible in May

May is the last month for certain indoor sowings. After June, the plants would not have time to produce before autumn.

Autumn leeks

Early May is one of the last chances to sow leeks that will be transplanted in July-August for an autumn-winter harvest. Sow in trays or seed modules outdoors (under cold cover if nights are still cool). Germination takes 10 to 15 days. Plants will be ready to transplant when they are pencil-thick (6 to 8 weeks after sowing).

Autumn and winter brassicas

To have Brussels sprouts, cabbages, autumn cauliflowers and broccoli ready in autumn, sow them indoors or under cover in May. Plants will be transplanted outdoors in June-July. Brussels sprouts in particular need a very long growing season: sow them without fail before mid-May.

Celeriac

If you have not yet sown your celeriac, it is still possible at the very beginning of May. Sow indoors in fine, moist compost. Germination is slow, and the seeds need light to germinate — place them on the surface without covering, or cover with the thinnest layer of vermiculite.

Herbs in May

May is THE month for herbs. All the Mediterranean varieties that have been struggling indoors for months can finally thrive in the open air and sunshine.

Basil: finally outdoors

Basil is the emblematic plant of May in the vegetable garden. Extremely frost-sensitive, it cannot tolerate temperatures below 10°C. After the Ice Saints, plant your basil pots in the ground or in a large container on the terrace, in the warmest, sunniest spot available. Pinch out the first flower buds to delay bolting and extend leaf production. For abundant basil, sow directly outdoors after May 15 — germination takes 8 to 10 days in warm weather.

Coriander, dill and chervil

Sow coriander directly outdoors from May onwards, in small amounts every three weeks as it bolts quickly. Plant it in light shade to slow bolting. Dill is sown directly in May as an ideal companion for cucumbers and lettuces. Chervil prefers cool, lightly shaded spots.

Thyme, rosemary, sage and lavender

These hardy Mediterranean herbs, robust and undemanding, are planted in May in well-drained soil in full sun. Do not over-water or fertilise them: their aroma is strongest when grown in poor, dry soil. Lavender planted now will flower this summer.

Mint

Beware — mint is a formidable spreader. Always plant it in a pot or a 15-litre bucket with no bottom, buried in the soil, to contain its underground runners. In May, divide existing clumps and install them in their containers or in an isolated corner of the garden.

Well-established herbs in the garden in May

Regional calendar

May is a month when differences between regions are still significant. Here are the priorities according to your climate zone.

Mediterranean climate (PACA, Languedoc, Corsica)

The season is already well advanced. In May you are already harvesting lettuces, radishes, peas and broad beans sown in winter. Priorities:

Atlantic climate (Brittany, Normandy, Loire Valley, Aquitaine)

May is ideal here: mild, moist and bright. Make the most of it:

Semi-continental climate (Île-de-France, Centre, Burgundy, Alsace)

Nights can still be cool early in the month. Follow a careful strategy:

Mountain climate (Alps, Pyrenees, Massif Central, Jura, Vosges)

At altitude, caution is needed until late in the month:

Essential May maintenance tasks

May is not only the planting month — it is also when established crops need attention.

Mulching: the absolute priority

Mulching is the most cost-effective action of May. Applied after planting or around germinated seedlings, it retains soil moisture (halving your watering), keeps the surface cool (roots dislike heat), limits weed growth, and gradually enriches the soil as it breaks down. Use straw (the easiest), wood chips, hay, dried grass clippings, shredded leaves or cardboard covered with organic matter. Recommended depth: 8 to 15 cm.

Weeding and hoeing

May sees an explosion of weeds spurred on by warmth and rain. Hoe regularly between rows as soon as the soil is not too wet. As the old saying goes, one good hoeing is worth two waterings. By breaking the surface crust, you limit evaporation and cut weeds before they root. Hand-pull any larger weeds too tough for the hoe.

Side-shooting tomatoes

May is the perfect time to take tomato side-shoot cuttings. These lateral shoots, removed from the junction between the main stem and a leaf, root easily in a glass of water or directly in a pot. In 10 to 15 days you get a free new plant. Systematically pinch out the side-shoots of indeterminate (cordon) tomatoes, keeping only the main stem — or two stems for vigorous varieties.

Staking and training climbers

Peas sown in March-April now urgently need their supports if not yet in place. Guide the first tendrils towards their supports. Install netting and trellises for climbing beans, cucumbers and climbing plants that will surge in May.

First earthing-up of potatoes

If your potatoes were planted in March-April, the stems are now 15 to 25 cm tall. Time for the first earthing-up: draw soil up around the stems to form a mound of 10 to 15 cm. This covers the stolons (future potatoes), protects forming tubers from light (which would turn them green and toxic) and improves drainage. A second earthing-up will be needed two to three weeks later.

Green pruning of tomatoes: essential from May

On cordon tomatoes, pinch out all side-shoots (lateral growths at the leaf axils) as soon as they reach 5 cm. Keep only a single main stem — or two for very vigorous plants. Repeat every two weeks. This focuses the plant's energy on fruit production rather than foliage growth. The result: larger, earlier tomatoes that are less susceptible to disease.

Watering: managing the rising heat

In May, temperatures climb and plants' water needs increase. Here are the right gestures for efficient, waste-free watering.

When to water?

Water in the evening or early morning to limit evaporation. Midday watering should be avoided not because it burns leaves (this myth is false for most plants) but because 50 to 70% of the water evaporates before penetrating the soil. In the evening, water has the whole night to soak in deeply.

How to water?

Always at the base, never on the foliage. Overhead watering encourages fungal diseases like blight on tomatoes and powdery mildew on squash and cucumbers. Drip irrigation or upturned water bottles buried at plant bases are the most water-efficient solutions.

How much to water?

It is better to water generously (10 to 15 litres per m²) once or twice a week than to water lightly every day. A deep watering encourages roots to dive down to where the soil stays cool and moist. Shallow daily watering promotes surface rooting, making plants dependent on frequent watering and vulnerable to drought. Learn to save water in the garden while keeping a productive vegetable plot.

Mistakes to avoid in May

Mistake #1: Planting before the last frost without protection

The temptation is strong when the first warm May days arrive. Resist, or prepare effective protection. A single night at -2°C can wipe out tomato or basil plants you have carefully nurtured for two months. Wait calmly until May 13 to 15 — that is a few days of patience in exchange for months of harvest.

Mistake #2: Skipping the hardening-off process

A plant grown at 20 to 22°C indoors and then planted straight out in full sun will suffer a violent thermal and light shock. Harden it off gradually: put it outside for an hour a day for 7 to 10 days, first in shade then progressively in sun. Water a little less during this period to acclimatise the plant to less frequent hydration.

Mistake #3: Not mulching immediately after planting

Planting without mulching straight away means creating extra work. Mulch on the same day you plant or once your seedlings have germinated. Waiting to "see if it takes" before mulching means letting the soil dry out, weeds taking hold, and the plants' energy being wasted on water stress.

Mistake #4: Sowing beans too early or too deep

Beans sown in soil still below 12°C will rot. Sown too deep (more than 5 cm), they struggle to germinate. The ideal depth is 3 to 4 cm, in soil at least 15°C. If germination takes more than 10 days, there is a temperature or moisture problem.

Mistake #5: Watering tomatoes every day

Irregular watering (drought then flooding) causes fruits to split and blossom end rot (black patch on the base of tomatoes). Water regularly and deeply, without letting the soil either dry out completely or stay waterlogged. A thick mulch naturally regulates moisture and simplifies the task.

Mistake #6: Planting too densely to "save space"

Tomatoes planted too close together compete with each other, share viruses more easily, and make access for care and harvesting difficult. Courgettes too close to melons can favour viruses transmitted by aphids. Respect recommended spacings: it means less ground covered in the short term, but more production over the whole season.

Week-by-week planner

For a typical temperate climate (Paris basin, Loire Valley), here is how to organise your May tasks, week by week.

Week 1 (May 1–7)

Week 2 (May 8–14)

Week 3 (May 15–21)

Week 4 (May 22–31)

"May is the month when the vegetable garden moves from promise to reality. Every plant put in the ground is a wager on summer, a joyful commitment to the season ahead."

May is a month of great generosity for the gardener: it finally brings the warmth, light and climatic security that have been awaited since the first February sowings. By following this calendar and adapting every decision to your region and local conditions, you will lay the foundations for a summer of abundant harvests. The July tomatoes, August courgettes, September melons — it all starts with the actions of May. Happy gardening!

Frequently Asked Questions

Can you plant tomatoes in May?

Yes, May is the ideal month to plant tomatoes in the ground, but only after the last frost risk has passed — traditionally after May 13 (the Ice Saints). Before that date, late frost is still possible in most regions. Wait until nights are consistently above 10°C and harden off your plants for 7 to 10 days before planting them out permanently.

What can I do after the last frost in May?

After the last frost risk has passed (around May 13-15 in most temperate regions), you can safely plant all tender crops outdoors: tomatoes, peppers, aubergines, courgettes, cucumbers, melons, beans and basil. This is the great spring planting window.

Which vegetables can be sown directly in May?

In May you can sow directly outdoors: French beans and climbing beans, courgettes and squash (in warm regions), sweetcorn, beetroot, carrots, radishes, lettuces, rocket, basil, dill, coriander and cucumbers. It is also the right time for successive sowings of radishes and lettuces.

Should I water after planting?

Yes, watering is crucial in May, especially after transplanting. Water thoroughly at planting time, then keep the soil evenly moist for the first 2 to 3 weeks to encourage rooting. Mulching immediately after planting greatly reduces watering needs and protects the soil from the increasing heat.