When to plant tomatoes in Geneva: 28 May – 28 July

In Geneva, tomato: sow for seedlings from 16 March to 6 June; plant into a greenhouse from 7 May to 28 July; plant out into open ground from 28 May to 28 July. For plants and seeds, the places nearby include Botanic (garden centre, 6 km) and Gamm Vert (garden centre, 8 km); addresses and opening hours are below.

Tomato in Geneva: soil, season and weather

In Geneva the soil, not frost, sets the date: the last frost is over around 10 April, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 28 May, 48 days later.

Last spring frost	10 April
Top 7 cm of soil at 15 °C	28 May, 48 days after the last frost
Into an unheated greenhouse	7 May – 28 July; May outside: 7.9 °C at night, 17.9 °C by day; card 16–27 °C
First autumn frost	17 November, 173 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	6 August – 6 October
Days left for picking	103
Daylight	13:03 on 6 April, 15:25 on 28 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, August, has 9 rainy days

Tomato in Geneva: care after planting

Planted on 28 May: in the first weeks water every 4 days.

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

28 May — feed: balanced (NPK)
25 June — feed: nitrogen

Pests and diseases of tomato 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 Geneva during the tomato season

No month of the season averages above the tomato card's 16–27 °C by day; the warmest, August, averages 25.9 °C. Months that stay below 16 °C even by day on average: October (15.8 °C) and November (9.3 °C). Nights average below 16 °C in every month of the season, from 1.9 °C to 14.9 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	17.9	7.9	125	13	14:57
June	23.5	13.1	104	13	15:45
July	25.8	14.9	88	11	15:26
August	25.9	14.7	80	9	14:12
September	20.8	11	85	10	12:36
October	15.8	6.9	113	11	10:59
November	9.3	1.9	122	14	9:28

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around Geneva, Chambéry is 15 days earlier and Aosta 37 days later.

City	Distance	Date	Difference
Annecy	32 km	2 June – 25 July	5 days later
Lausanne	52 km	2 June – 31 July	5 days later
Chambéry	72 km	13 May – 31 July	15 days earlier
Sion	94 km	21 June – 29 June	24 days later
Fribourg	102 km	5 June – 17 July	8 days later
Aosta	105 km	from 4 July	37 days later

Where to buy tomato plants and seeds near Geneva

Buy plants ready to set out from 28 May to 28 July (from 7 May to 28 July for an unheated greenhouse); seed for raising your own is sown from 16 March to 6 June. Within 15 km of Geneva OpenStreetMap lists 16 garden centres, 2 farm-supply shops, 8 markets and 23 farm shops (collected 27 October 2026).

Gamm Vert — garden centre
Chemin des Trois Noyers 33, 74100 Vétraz-Monthoux · Mon–Fri 09:00–12:00, 14:00–19:00; Sat 09:00–19:00; Sun 09:00–12:30, 14:30–18:00 · 8 km · magasin.gammvert.fr
Botanic — garden centre
Rue des Biches 14, 74100 Ville-la-Grand · Mon–Sat 09:00–19:00; Sun 09:30–12:30, 14:00–18:00; Aug 15 closed · 10 km · botanic.com
Botanic — garden centre
Rue du Mont Blanc 500, 01630 Saint-Genis-Pouilly · Mon–Sat 09:00–19:00; Sun 09:30–12:30, 14:00–18:00 · 11 km · botanic.com
Botanic — garden centre
Rue René Cassin 35 · Mon–Sun 09:00–12:00, 14:00–19:00; Aug 15 14:00–19:00 · 6 km · botanic.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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