When to plant watermelons in Mons: 10 June – 10 August

In Mons, watermelon: sow for seedlings from 22 April to 13 July; plant into a greenhouse from 20 May to 10 August; plant out into open ground from 10 June to 10 August. For plants and seeds, the places nearby include Ferme de Champré (farm shop, 12 km) and Au fil des saisons (farm shop, 13 km); addresses and opening hours are below.

Watermelon 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 18 °C — the minimum on the watermelon card — only around 10 June, 61 days later.

Last spring frost	10 April
Top 7 cm of soil at 18 °C	10 June, 61 days after the last frost
Into an unheated greenhouse	20 May – 10 August; May outside: 8.5 °C at night, 18.4 °C by day; card 18–35 °C
First autumn frost	19 November, 162 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	8 August – 8 October
Days left for picking	103
Daylight	15:21 on 13 May, 16:21 on 10 June
Watering outdoors when fruiting (card)	every 5 days; the driest month, August, has 12 rainy days

The same dates in Mons hold for Cucumber, Bell Pepper, Eggplant, Zucchini and Pumpkin.

Watermelon in Mons: care after planting

Planted on 10 June: in the first weeks water every 5 days.

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

10 June — feed: balanced (NPK)

Pests and diseases of watermelon 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 watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, August, averages 23.5 °C. Months that stay below 18 °C even by day on average: October (15.7 °C) and November (10.1 °C). Nights average below 18 °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
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

Watermelon in nearby cities

Around Mons, Ghent is 10 days earlier and Namur 1 day later.

City	Distance	Date	Difference
Charleroi	35 km	10 June – 6 August	same day
Brussels	53 km	8 June – 13 August	2 days earlier
Namur	65 km	11 June – 6 August	1 day later
Lille	66 km	11 June – 12 August	1 day later
Ghent	69 km	31 May – 15 August	10 days earlier
Leuven	71 km	31 May – 13 August	10 days earlier

Where to buy watermelon plants and seeds near Mons

Buy plants ready to set out from 10 June to 10 August (from 20 May to 10 August for an unheated greenhouse); seed for raising your own is sown from 22 April to 13 July. 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).

Ferme de Champré — farm shop
Rue du Champré 415, 7300 Boussu · 12 km
Au fil des saisons — farm shop
Rue du Thy 25, 7870 Lens · 13 km
Les paniers de Maryse — farm shop
Rue de Stambruges 13, 7332 Neufmaison · 14 km
La Ferme du Bosquetiau — farm shop
Wed, Thu 14:00–18:00; Fri 09:00–18:00; Sat 09:00–17:00; Sun 10:00–12:00 · 15 km · lafermedubosquetiau.be

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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