The sowing calendar month by month (outdoor & under cover)

A sowing calendar is never a calendar of dates: it is a calendar of conditions. Two gardens 200 kilometers apart may have a six-week difference for the same crop. Before going through the months, this guide therefore provides the three reference points that let you adapt any calendar to your garden—followed by the month-by-month details, both outdoors and under cover.

The three reference points that shift everything

1. Your last frost date

This is the most important factor in the vegetable garden, yet it is rarely known. In France, it ranges roughly from mid-March on the Mediterranean coast and the southern Atlantic coast to mid-June in the middle mountains, with a broad area around mid-May. The tradition of the Ice Saints (May 11–13) is a cautious guideline that works for much of the country, but is too late in the south and too early at higher elevations.

Once you know this date, everything can be calculated backward: tomatoes are sown under cover 6 to 8 weeks beforehand, and squash 3 to 4 weeks beforehand. Sowing earlier does not save time—you end up with leggy seedlings that will suffer when transplanted.

2. Soil temperature, not air temperature

This is the classic mistake made during the first fine weekend in March. A seed responds not to mild air temperatures but to the warmth of the soil. Here are some useful thresholds:

A kitchen thermometer pushed 5 cm into the soil in the morning gives you the answer in ten seconds. It is the best investment you can make for your vegetable garden.

3. Direct sowing or sowing in pots?

The rule can be summed up in one sentence: anything that hates being disturbed should be sown in place.

• Must be sown in place — carrot, radish, parsnip, turnip, lamb's lettuce, spinach, pea, broad bean, bean. Their taproots do not tolerate transplanting well.
• Preferably in pots — tomato, pepper, eggplant, cabbage, leek, celery: with their long growing cycles, you gain several weeks in the season.
• Optional — squash, zucchini, cucumber, lettuce, basil. Pots let you get a head start without difficulty, provided you transplant while the plants are young.

The technique for each method is explained in detail in How to sow seeds in cotton, pots, or directly in the ground.

Winter: January and February

Few sowings, but the month that determines the year. This is the time to establish your growing plan, check your seed lots, and prepare your containers.

January

• In a heated shelter (20 °C minimum): eggplant, chili peppers, bell peppers — only if you have horticultural lighting. Without supplemental light, the plants become leggy and you lose the head start you were hoping for.
• Under a cold frame: winter lettuce, spinach, lamb’s lettuce.
• In a warm place, without any particular lighting: seeds requiring cold stratification (trees, shrubs, and some perennials) should be placed in the refrigerator now to break dormancy in spring.

A useful step: perform a germination test on seed lots that are more than three years old. You will know which ones to buy again before the February rush.

February

• Under cover: leek, celery, storage onion, parsley, early cabbage. Tomatoes at the end of the month in the south only.
• In the ground, if the soil is drained and not frozen: broad beans, round-seeded peas, shallots, spring garlic.

The soil is “drained” when a handful of pressed soil leaves no water between your fingers and crumbles when you open your hand. Working waterlogged soil compacts it permanently.

Spring: March, April, May

The main season. Find all the varieties concerned in our Spring Sowing collection.

March

• In the ground: radish, early carrot, spinach, spring lettuce, turnip, peas, parsnip.
• Under cover: tomato (the reference month in most regions), beetroot, summer cabbage, basil at the end of the month.

Something to watch out for: move the mulch away from your beds two weeks before sowing. Covered soil stays cold, and you lose precisely the head start you are seeking.

April

• In the ground: beans at the end of the month, depending on the region; beetroot, chard, squash and zucchini in the south, sunflower, nasturtium, calendula, phacelia.
• Under cover: zucchini, cucumber, melon, late eggplant, annual herbs.

April is also the right month to put companion planting into practice, starting at sowing rather than afterward.

May

• In the ground, after the last frost: beans, sweet corn, squash, cucumber, melon, watermelon, basil.
• Transplants: tomatoes, peppers, eggplants, zucchini grown under cover.

Transplanting technique: take the plants outside one week beforehand, for a few hours each day, to acclimatize them gradually (this is called hardening off). A plant moved directly from the greenhouse into full wind loses two weeks of growth.

Summer: June, July, August

The season for succession sowings—the ones we most often forget, yet which make the difference between a vegetable garden that produces for two months and one that produces for six. See the collection Summer sowings.

June

• Open ground: beans (2nd sowing), chicory, fennel, autumn turnips, summer lettuce, winter leeks for transplanting.
• Green manures on cleared beds: phacelia, buckwheat.

July

• Open ground: winter carrots, late beets, kale, frisée chicory, beans (last sowing in the north).

The problem in July is germination. The soil dries out on the surface faster than the seed can germinate. Two solutions: sow deeper than in spring (1.5 times deeper), and cover the row with fleece or a board for three days to retain moisture—removing it as soon as the first shoots appear.

August

• Open ground: lamb's lettuce, winter spinach, winter radishes, autumn lettuce, turnips, arugula, watercress.

This is the decisive month for winter harvests. A successful sowing of lamb's lettuce in August produces salads from November to February; the same sowing in October will yield almost nothing.

Autumn: September to December

Collection Autumn sowings.

September

• Open ground: lamb's lettuce, spinach, winter lettuce under a cold frame, arugula, green manures (rye, clover, mustard).
• Sowings of biennial herbs: parsley, chervil, coriander—they emerge slowly and resume vigorous growth in spring.

October

• Open ground: white and purple garlic, white onions, broad beans, and winter peas in mild regions.
• Trees and shrubs: this is the time to sow species requiring natural stratification, left outdoors all winter—the cold does the work for you.

November and December

• Open ground: garlic (until early December), gray shallots in mild regions.
• The rest of the work is preparation: compost, thick mulch, and above all never leave a bed bare over winter.

And off-season sowings

A few species fall entirely outside the calendar: indoor herbs (basil, chives, parsley), sprouted seeds, microgreens, and tropical species grown in pots. They only need a stable temperature and light. Our Year-round sowing collection brings them together—useful for not being left empty-handed in January.

Frequently asked questions

I sowed too early—what should I do?

If the seedlings are leggy (long, pale stems), repot them deeper, burying part of the stem—tomatoes produce adventitious roots and recover very well. For other species, it is often better to sow again: two weeks later, they can make up the difference with a few days of growth.

How can I tell whether a sowing has failed or is just taking a long time?

Compare it with the theoretical germination time: 3 to 5 days for a radish, 6 to 10 for lettuce, 8 to 15 for a tomato, and up to 3 weeks for parsley or a carrot in cold soil. Beyond twice that time, dig up a seed: if it is soft and decomposed, it has rotted; if it is intact, it is simply waiting for warmer conditions.

Should I follow the lunar calendar?

It is an old tradition, without solid scientific validation, but it does have real practical merit: it imposes a regular rhythm for spending time in the garden. If it helps you stick to it, it is useful. We documented it in Waxing or waning moon.

Can I sow at a different time than indicated in this calendar?

Yes, and it is even recommended for short-cycle species. Sowing 20 radishes every two weeks is better than sowing 100 all at once: you harvest continuously instead of losing everything at once.

Key points

A sowing calendar is read through three filters: your last frost date, your soil temperature, and the species' tolerance for transplanting. Once you have integrated these three factors, you no longer need a calendar: you know how to read your garden.

To go further

• Sowing in April: what should you plant in the vegetable garden this month?
• Autumn vegetable garden: what to sow and when to harvest?
• Sowing green manures: benefits, types, and calendar
• How do you create a permaculture vegetable garden?

Discover our varieties organized by season: spring, summer, autumn, and year-round.