When to plant cucumbers in Rennes: 1 June – 13 September

In Rennes, cucumber: sow for seedlings from 13 April to 16 August; plant into a greenhouse from 11 May to 13 September; plant out into open ground from 1 June to 13 September. For plants and seeds, the places nearby include Succulente Design Végétal (garden centre, 0 km) and Culture Indoor (garden centre, 4 km); addresses and opening hours are below.

Cucumber in Rennes: soil, season and weather

In Rennes the soil, not frost, sets the date: the last frost is over around 12 March, but the top 7 cm of soil reaches 18 °C — the minimum on the cucumber card — only around 1 June, 81 days later.

Last spring frost	12 March
Top 7 cm of soil at 18 °C	1 June, 81 days after the last frost
Into an unheated greenhouse	11 May – 13 September; May outside: 9.4 °C at night, 19.1 °C by day; card 18–25 °C
First autumn frost	28 November, 180 days after the start
Days in the bed to the first harvest (card)	34
First harvest, if planted in this window	5 July – 17 October
Days left for picking	146
Daylight	14:39 on 4 May, 15:47 on 1 June
Watering outdoors when fruiting (card)	every 2 days; the driest month, August, has 9 rainy days

The same dates in Rennes hold for Bell Pepper, Eggplant, Zucchini, Pumpkin and Watermelon.

Cucumber in Rennes: care after planting

Planted on 1 June: in the first weeks water every 4 days.

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

8 June — feed: nitrogen

Pests and diseases of cucumber 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 Rennes during the cucumber season

No month of the season averages above the cucumber card's 18–35 °C by day; the warmest, August, averages 24.4 °C. Months that stay below 18 °C even by day on average: October (17.4 °C) and November (12.4 °C). Nights average below 18 °C in every month of the season, from 6.1 °C to 14.4 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
June	22.8	12.9	83	11	16:02
July	24.3	14.3	50	8	15:41
August	24.4	14.4	48	9	14:21
September	21.5	12.4	58	9	12:38
October	17.4	9.8	87	12	10:54
November	12.4	6.1	78	12	9:17

ERA5 2016–2025, Open-Meteo

Cucumber in nearby cities

Around Rennes, Nantes is 4 days earlier and Caen 14 days later.

City	Distance	Date	Difference
Nantes	99 km	28 May – 14 September	4 days earlier
Angers	110 km	28 May – 12 September	4 days earlier
Le Mans	140 km	31 May – 9 September	1 day earlier
Caen	154 km	15 June – 20 September	14 days later
Quimper	180 km	15 June – 24 September	14 days later
Tours	194 km	31 May – 12 September	1 day earlier

Where to buy cucumber plants and seeds near Rennes

Buy plants ready to set out from 1 June to 13 September (from 11 May to 13 September for an unheated greenhouse); seed for raising your own is sown from 13 April to 16 August. Within 15 km of Rennes OpenStreetMap lists 21 garden centres, 5 farm-supply shops, 3 plant nurseries, 41 markets and 19 farm shops (collected 20 October 2026).

Lysadis — garden centre
Rue des Comptoirs 51, 35410 Châteaugiron · Mon–Fri 09:00–12:30, 14:00–19:00; Sat 09:00–19:00 · 15 km · lysadis.fr
Succulente Design Végétal — garden centre
Rue de Bertrand 9, 35000 · Tue–Sat 11:00–19:00 · 0 km · succulentedesignvegetal.com
Culture Indoor — garden centre
Rue des Landelles 30, 35135 Chantepie · Tue–Fri 10:30–19:00; Sat 10:30–18:00 · 4 km · cultureindoor.com
Jardiland — garden centre
Avenue du Phare du Grand Jardin, 35520 La Mézière · Mon–Fri 09:30–12:30, 14:00–19:00; Sat 09:30–19:00; Sun 09:30–13:00, 14:00–18:30 · 11 km · jardiland.com

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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