When to plant watermelons in Grenoble: 28 June – 16 July

In Grenoble, watermelon: sow for seedlings from 10 May to 18 June; plant into a greenhouse from 7 June to 16 July; plant out into open ground from 28 June to 16 July. For plants and seeds, the places nearby include La Ferme des Maquis (farm shop, 5 km); addresses and opening hours are below.

Watermelon in Grenoble: soil, season and weather

In Grenoble the soil, not frost, sets the date: the last frost is over around 5 May, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 28 June, 54 days later.

Last spring frost	5 May
Top 7 cm of soil at 18 °C	28 June, 54 days after the last frost
Into an unheated greenhouse	7 June – 16 July; June outside: 10.1 °C at night, 20.6 °C by day; card 18–35 °C
First autumn frost	25 October, 119 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	26 August – 13 September
Days left for picking	60
Daylight	15:22 on 31 May, 15:37 on 28 June
Watering outdoors when fruiting (card)	every 5 days; the driest month, July, has 9 rainy days

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

Watermelon in Grenoble: care after planting

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

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

28 June — 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 Grenoble during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, August, averages 22.8 °C. Months that stay below 18 °C even by day on average: October (14.1 °C). Nights average below 18 °C in every month of the season, from 4.3 °C to 11.7 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
June	20.6	10.1	130	13	15:37
July	22.7	11.7	83	9	15:19
August	22.8	11.7	87	8	14:08
September	18	7.7	101	11	12:35
October	14.1	4.3	128	11	11:01

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

All the nearest cities on our list plant watermelon earlier than Grenoble; the closest date is in Annecy, 9 days earlier.

City	Distance	Date	Difference
Chambéry	45 km	3 June – 11 August	25 days earlier
Valence	70 km	29 May – 12 August	30 days earlier
Annecy	86 km	19 June – 5 August	9 days earlier
Lyon	93 km	27 May – 16 August	32 days earlier
Saint-Étienne	108 km	14 June – 8 August	14 days earlier
Geneva	117 km	8 June – 8 August	20 days earlier

Where to buy watermelon plants and seeds near Grenoble

Buy plants ready to set out from 28 June to 16 July (from 7 June to 16 July for an unheated greenhouse); seed for raising your own is sown from 10 May to 18 June. Within 15 km of Grenoble OpenStreetMap lists 17 garden centres, 4 plant nurseries, 55 markets and 19 farm shops (collected 20 October 2026).

Marché Paul Éluard — market
Tue, Fri 07:00–13:00; Thu 15:00–19:00 · 4 km
Marché Saint-Bruno — market
Tue–Sun 06:00–13:00 · 1 km
Marché alimentaire des producteurs Saint-André — market
Sat, Sun 07:00–13:30 · 1 km
La Ferme des Maquis — farm shop · sells: goat cheese
Route des Maquis 165, 38400 Saint-Martin-d'Hères · Wed, Fri 16:00–19:00; Sat 10:00–12:00, 16:00–19:00 · 5 km · fermedesmaquis.fr

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.

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