Vegetable garden calendar for France: sowing dates by region

Between Lille and Marseille, the tomato is planted seven weeks apart. In our data, the Bonbon de Gembloux goes out from 25 March in the south of France. In the North, not before 15 May. And how to place yourself if your garden falls between two.

Which region of the calendar is your garden in?

Météo-France distinguishes five climates in mainland France. The app's calendar counts four regions for France, plus one for the Atlantic coast of Spain and Portugal. The mountains have no column. Up there, the date depends mostly on altitude.

A frost day is a day when the minimum falls to 0 °C or below. The figures are averages over 1991 to 2020. Strasbourg has one and a half times as many frost days as Lille over the year. In April, the East still freezes most often, 2.1 days on average, with a record of -5.6 °C. This late frost explains almost all the differences in the next table.

In Brittany, Normandy or the Paris Basin, take the "Belgium and northern France" column. The Bordeaux area and the Landes go with the South-west. Languedoc, Provence and Corsica with the South. Alsace, Lorraine and Franche-Comté with the East.

The calendar for eight vegetables, region by region

Each date is a window. It opens on the first day when the move makes sense. It closes on the last day when it still gives a harvest. The dates come from the app's catalogue, which describes each crop for each climate. In the table below, "North" is Belgium and northern France, "South-west" is south-west France, "South" is the south of France and "East" is eastern France.

For the tomato, the catalogue only gives a planting date by variety. The Bonbon de Gembloux is one of the eight tomatoes described in the four French climates. We therefore took it as a landmark. The other varieties shift a little. In the North, the Marmande is planted from 10 to 31 May and the Cœur de bœuf from 15 May to 15 June.

Why the south of France sows peas and salad twice

In the south of France, peas are sown in winter, from 15 January to 3 March, then in autumn, from 1 October to 30 November. Nothing in between. Summer blocks everything. At Marignane, it is 30 °C or more on 50.6 days a year on average, against 6.8 days at Lille-Lesquin. And the pea seed germinates poorly in the warm. According to University of California data, it comes up best in soil at 24 °C. Above 29 °C, it no longer comes up.

Salad follows the same logic. In the south, it is sown until the end of April, then starts again on 20 August. In the North, summer stays mild enough to sow without a break, from 1 February to 31 August. The potato also has two windows in the south. The first runs from mid-January to the end of April, the second from mid-August to mid-September.

If you come from the North and garden in the South, your calendar has a gap in summer and a second season in autumn.

The East: waiting for the frost to leave

Strasbourg-Entzheim has 59.5 frost days a year. There are still 8.4 in March and 2.1 in April. So frost-tender crops wait longer in the East than in the North, even though it lies further south. Beans are only sown from 31 May. In our data for the North, they start from 15 April.

Summer makes up some of the delay. Strasbourg has 18.4 days at 30 °C or more, against 6.8 at Lille. The planting window for tomatoes is short there, from 14 to 27 May. Sown in the warm on 2 April and planted on 14 May, the plant spends six weeks in its pot.

Between two regions, at altitude or under glass: how to shift

Your garden falls into no box? Two landmarks are enough to redo the calculation at home.

The first is the last frost. Frost-tender plants (tomato, courgette, bean) go out when frost no longer returns. If your town freezes three weeks later than the station for your region, shift their dates by three weeks. Shift the sowing in the warm by the same amount, so the plants do not age in their pots. In the mountains, we have no column. Start from your own last frosts.

The second is soil temperature. A seed does not look at the calendar. It reacts to the warmth of the soil. The University of California figures show it well.

A bean sown too early therefore gains nothing. It waits in cold soil and may rot before coming up.

Under a cold greenhouse or against a south-facing wall, the soil warms earlier. We have no reliable figure for this head start. Your thermometer will give it to you.

Further reading

Tomato planting dates depend mostly on the last frosts. The guide The Ice Saints goes over the records. To understand why a plant moves faster in the warm, read Growing degree days. For sowings at the end of summer, What to sow in September gives the cut-off date for each vegetable.

The seeds whose window is open this month are in the To sow now collection. For the dates of your own packets, calculated for your address, go through the app.

Photo: Jason Zeis, Unsplash