When to plant tomatoes in Saint-Étienne: 30 May – 28 July

In Saint-Étienne, tomato: sow for seedlings from 18 March to 6 June; plant into a greenhouse from 9 May to 28 July; plant out into open ground from 30 May to 28 July. For plants and seeds, the places nearby include Jardiland (garden centre, 3 km) and Gamm Vert (garden centre, 8 km); addresses and opening hours are below.

Tomato in Saint-Étienne: soil, season and weather

In Saint-Étienne the soil, not frost, sets the date: the last frost is over around 13 April, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 30 May, 47 days later.

Last spring frost	13 April
Top 7 cm of soil at 15 °C	30 May, 47 days after the last frost
Into an unheated greenhouse	9 May – 28 July; May outside: 8 °C at night, 17.7 °C by day; card 16–27 °C
First autumn frost	17 November, 171 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	8 August – 6 October
Days left for picking	101
Daylight	13:08 on 8 April, 15:22 on 30 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, August, has 8 rainy days

Tomato in Saint-Étienne: care after planting

Planted on 30 May: in the first weeks water every 4 days.

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

30 May — feed: balanced (NPK)
27 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 Saint-Étienne during the tomato season

No month of the season averages above the tomato card's 16–27 °C by day; the warmest, August, averages 25.7 °C. Months that stay below 16 °C even by day on average: November (9.9 °C). Nights average below 16 °C in every month of the season, from 2.9 °C to 14.5 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	17.7	8	117	16	14:52
June	23.3	12.9	99	14	15:39
July	25.5	14.5	68	9	15:21
August	25.7	14.5	64	8	14:09
September	21	11.1	71	10	12:35
October	16.3	7.7	105	11	11:01
November	9.9	2.9	83	12	9:32

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around Saint-Étienne, Valence is 29 days earlier and Grenoble 21 days later.

City	Distance	Date	Difference
Lyon	50 km	2 May – 5 August	28 days earlier
Valence	70 km	1 May – 1 August	29 days earlier
Grenoble	108 km	20 June – 5 July	21 days later
Clermont-Ferrand	109 km	6 June – 23 July	7 days later
Chambéry	120 km	13 May – 31 July	17 days earlier
Annecy	145 km	2 June – 25 July	3 days later

Where to buy tomato plants and seeds near Saint-Étienne

Buy plants ready to set out from 30 May to 28 July (from 9 May to 28 July for an unheated greenhouse); seed for raising your own is sown from 18 March to 6 June. Within 15 km of Saint-Étienne OpenStreetMap lists 12 garden centres, 5 farm-supply shops, 1 plant nursery, 21 markets and 13 farm shops (collected 20 October 2026).

Gamm Vert — garden centre
Rue du 17 Octobre 1961 4, 42400 Saint-Chamond · Mon–Fri 09:00–12:00, 14:00–19:00; Sat 09:00–19:00 · 8 km · gammvert.fr
Jardinerie Briat / FranceRurale — garden centre
Route de Saint-Étienne 13, 42400 Saint-Chamond · Mon–Sat 08:30–12:00, 14:00–18:30 · 9 km · jardinerie-briat.fr
Jardiland — garden centre
Mon–Sat 09:30–12:00, 14:00–19:00; Sun 09:30–12:30, 14:30–18:30 · 3 km · jardiland.com
Botanic — garden centre
Mon–Sat 09:00–19:00; Sun 09:00–12:30, 14:00–18:30 · 12 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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