When to plant tomatoes in Colmar: 31 May – 28 July

In Colmar, tomato: sow for seedlings from 19 March to 6 June; plant into a greenhouse from 10 May to 28 July; plant out into open ground from 31 May to 28 July. For plants and seeds, the places nearby include Trèfle vert (garden centre, 3 km) and Auxine (garden centre, 4 km); addresses and opening hours are below.

Tomato in Colmar: soil, season and weather

In Colmar the soil, not frost, sets the date: the last frost is over around 20 April, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 31 May, 41 days later.

Last spring frost	20 April
Top 7 cm of soil at 15 °C	31 May, 41 days after the last frost
Into an unheated greenhouse	10 May – 28 July; May outside: 8 °C at night, 16.6 °C by day; card 16–27 °C
First autumn frost	17 November, 170 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	9 August – 6 October
Days left for picking	100
Daylight	13:17 on 9 April, 15:45 on 31 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, September, has 12 rainy days

Tomato in Colmar: care after planting

Planted on 31 May: in the first weeks water every 4 days.

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

31 May — feed: balanced (NPK)
28 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 Colmar during the tomato season

No month of the season averages above the tomato card's 16–27 °C by day; the warmest, August, averages 23.2 °C. Months that stay below 16 °C even by day on average: October (14.4 °C) and November (8 °C). Nights average below 16 °C in every month of the season, from 2.3 °C to 14.1 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	16.6	8	101	15	15:10
June	21.8	12.9	102	15	16:02
July	23.1	13.9	77	13	15:41
August	23.2	14.1	81	13	14:21
September	18.9	10.7	69	12	12:38
October	14.4	7.2	82	12	10:54
November	8	2.3	92	14	9:17

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

All the nearest cities on our list plant tomato earlier than Colmar; the closest date is in Zurich, 2 days earlier.

City	Distance	Date	Difference
Mulhouse	37 km	13 May – 28 July	18 days earlier
Freiburg im Breisgau	38 km	13 May – 27 July	18 days earlier
Basel	60 km	14 May – 31 July	17 days earlier
Strasbourg	62 km	12 May – 31 July	19 days earlier
Nancy	110 km	16 May – 28 July	15 days earlier
Zurich	118 km	29 May – 27 July	2 days earlier

Where to buy tomato plants and seeds near Colmar

Buy plants ready to set out from 31 May to 28 July (from 10 May to 28 July for an unheated greenhouse); seed for raising your own is sown from 19 March to 6 June. Within 15 km of Colmar OpenStreetMap lists 10 garden centres, 6 farm-supply shops, 1 plant nursery, 1 market and 8 farm shops (collected 27 October 2026).

Truffaut — garden centre
Mon–Fri 09:30–12:30, Mon–Sat 14:00–19:00, Sat 09:30–19:00 · 5 km · truffaut.com
Trèfle vert — garden centre
Mon–Fri 09:00–12:00, 14:00–18:30; Sat 09:00–12:00, 14:00–18:00 · 3 km
Auxine — garden centre
Tue–Sat 09:00–18:00 · 4 km
Trèfle Vert Munster — garden centre
Mon–Fri 09:00–12:00, 14:00–18:30; Sat 09:00–12:00, 14:00–18:00 · 15 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.

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