When to plant watermelons in Nantes: 28 May – 20 August

In Nantes, watermelon: sow for seedlings from 9 April to 23 July; plant into a greenhouse from 7 May to 20 August; plant out into open ground from 28 May to 20 August.

Watermelon in Nantes: soil, season and weather

In Nantes the soil, not frost, sets the date: the last frost is over around 7 March, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 28 May, 82 days later.

Last spring frost	7 March
Top 7 cm of soil at 18 °C	28 May, 82 days after the last frost
Into an unheated greenhouse	7 May – 20 August; May outside: 10.4 °C at night, 19.6 °C by day; card 18–35 °C
First autumn frost	29 November, 185 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	26 July – 18 October
Days left for picking	126
Daylight	14:22 on 30 April, 15:32 on 28 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, July, has 8 rainy days

The same dates in Nantes hold for Cucumber, Bell Pepper, Eggplant, Zucchini and Pumpkin.

Watermelon in Nantes: care after planting

Planted on 28 May: in the first weeks water every 5 days.

Feeding, by the card’s schedule from that day:

28 May — feed: balanced (NPK)

Pests and diseases of watermelon to watch for:

Dates count from the first planting day of the window above; a later planting moves them by as many days.

Weather in Nantes during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, August, averages 25.5 °C. Months that stay below 18 °C even by day on average: November (12.8 °C). Nights average below 18 °C in every month of the season, from 6.4 °C to 15.5 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	19.6	10.4	59	12	15:04
June	23.4	14.1	69	11	15:54
July	25.2	15.4	37	8	15:34
August	25.5	15.5	40	7	14:17
September	22.3	13.1	56	10	12:37
October	18	10.4	102	12	10:57
November	12.8	6.4	90	13	9:22

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

2 of the nearest cities share Nantes's date.

City	Distance	Date	Difference
Angers	80 km	28 May – 18 August	same day
Rennes	99 km	1 June – 19 August	4 days later
La Rochelle	122 km	28 May – 2 September	same day
Le Mans	157 km	31 May – 15 August	3 days later
Poitiers	160 km	30 May – 10 August	2 days later
Tours	170 km	31 May – 18 August	3 days later

Where to buy watermelon plants and seeds near Nantes

Buy plants ready to set out from 28 May to 20 August (from 7 May to 20 August for an unheated greenhouse); seed for raising your own is sown from 9 April to 23 July. Within 15 km of Nantes OpenStreetMap lists 18 garden centres, 1 plant nursery, 51 markets and 22 farm shops (collected 20 October 2026).

Marché du quartier de la Chabossière — market
Sat 08:30–12:30 · 10 km · ville-coueron.fr
Marché de la Bottière — market
Place du Commandant Cousteau · Wed 16:00–19:30 · 4 km
La halle de Grignon — market
Wed 8:30–13:00 · 6 km
Place du marché — market
Fri, Sun 08:00–13:00 · 9 km

Each window starts on the Greenly calendar date and ends on the last day that still leaves the crop’s days to harvest (from its card) before the average first autumn frost, plus six weeks of picking for crops harvested over weeks (tomatoes, peppers, aubergines, cucumbers, courgettes, pumpkins, watermelons, beans) — our rule; earlier in the window is safer.

Questions