When to plant tomatoes in Mons: 16 May – 30 July

In Mons, tomato: sow for seedlings from 4 March to 8 June; plant into a greenhouse from 25 April to 30 July; plant out into open ground from 16 May to 30 July. For plants and seeds, the places nearby include Acar & Fils (garden centre, 5 km) and Pépinières Jacques Mainil (garden centre, 5 km); addresses and opening hours are below.

Tomato in Mons: soil, season and weather

In Mons 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 16 May, 36 days later.

Last spring frost	10 April
Top 7 cm of soil at 15 °C	16 May, 36 days after the last frost
Into an unheated greenhouse	25 April – 30 July; April outside: 4.9 °C at night, 14.4 °C by day; card 16–27 °C
First autumn frost	19 November, 187 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	25 July – 8 October
Days left for picking	117
Daylight	12:27 on 25 March, 15:30 on 16 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, August, has 12 rainy days

Tomato in Mons: care after planting

Planted on 16 May: in the first weeks water every 4 days.

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

16 May — feed: balanced (NPK)
13 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 Mons during the tomato season

No month of the season averages above the tomato card's 16–27 °C by day; the warmest, August, averages 23.5 °C. Months that stay below 16 °C even by day on average: October (15.7 °C) and November (10.1 °C). Nights average below 16 °C in every month of the season, from 4.7 °C to 14.2 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	18.4	8.5	68	13	15:27
June	22.1	12.7	79	11	16:25
July	23.2	13.8	67	11	16:02
August	23.5	14.2	61	12	14:34
September	20.3	11.8	66	11	12:41
October	15.7	9.2	75	13	10:48
November	10.1	4.7	69	13	9:02

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

4 of the nearest cities share Mons's date.

City	Distance	Date	Difference
Charleroi	35 km	16 May – 26 July	same day
Brussels	53 km	16 May – 2 August	same day
Namur	65 km	16 May – 26 July	same day
Lille	66 km	16 May – 1 August	same day
Ghent	69 km	13 May – 4 August	3 days earlier
Leuven	71 km	10 May – 2 August	6 days earlier

Where to buy tomato plants and seeds near Mons

Buy plants ready to set out from 16 May to 30 July (from 25 April to 30 July for an unheated greenhouse); seed for raising your own is sown from 4 March to 8 June. Within 15 km of Mons OpenStreetMap lists 21 garden centres, 1 farm-supply shop, 2 plant nurseries, 8 markets and 15 farm shops (collected 27 October 2026).

Acar & Fils — garden centre
Chaussée du Roi Baudouin 105 · Tue–Fri 10:00–12:00, 14:00–18:00; Sat 09:00–12:00, 13:30–17:00 · 5 km · ets-acar.be
Pépinières Jacques Mainil — garden centre
Rue de Douvrain 26, 7011 Ghlin · 5 km · pepinieresmainil.be
Aveve — garden centre
Chaussée du Roeulx 351 · Mon–Fri 09:00–18:30; Sat 09:00–18:00; Sun closed · 15 km · aveve.be
Centragro Garden — garden centre
Rue Bois Bourdon 150 · Mon–Sat 09:00–18:00 · 7 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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