When to plant watermelons in Ostrava: 8 June – 31 July

In Ostrava, watermelon: sow for seedlings from 20 April to 3 July; plant into a greenhouse from 18 May to 31 July; plant out into open ground from 8 June to 31 July.

Watermelon in Ostrava: soil, season and weather

In Ostrava the soil, not frost, sets the date: the last frost is over around 19 April, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 8 June, 50 days later.

Last spring frost	19 April
Top 7 cm of soil at 18 °C	8 June, 50 days after the last frost
Into an unheated greenhouse	18 May – 31 July; May outside: 8.3 °C at night, 18.3 °C by day; card 18–35 °C
First autumn frost	9 November, 154 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	6 August – 28 September
Days left for picking	95
Daylight	15:11 on 11 May, 16:12 on 8 June
Watering outdoors when fruiting (card)	every 5 days; the driest month, November, has 10 rainy days

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

Watermelon in Ostrava: care after planting

Planted on 8 June: in the first weeks water every 5 days.

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

8 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 Ostrava during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, August, averages 25 °C. Months that stay below 18 °C even by day on average: October (14.7 °C) and November (8.1 °C). Nights average below 18 °C in every month of the season, from 2.2 °C to 15 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
June	23.6	13.5	83	14	16:19
July	24.8	14.8	97	14	15:56
August	25	15	103	11	14:30
September	20.1	11.2	102	11	12:40
October	14.7	6.9	74	12	10:50
November	8.1	2.2	54	10	9:06

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

All the nearest cities on our list plant watermelon earlier than Ostrava; the closest date is in Katowice, 2 days earlier.

City	Distance	Date	Difference
Katowice	73 km	6 June – 7 August	2 days earlier
Olomouc	77 km	3 June – 28 July	5 days earlier
Zlín	79 km	6 June – 28 July	2 days earlier
Opole	97 km	2 June – 9 August	6 days earlier
Kraków	123 km	6 June – 23 July	2 days earlier
Częstochowa	126 km	5 June – 1 August	3 days earlier

Where to buy watermelon plants and seeds near Ostrava

Buy plants ready to set out from 8 June to 31 July (from 18 May to 31 July for an unheated greenhouse); seed for raising your own is sown from 20 April to 3 July. Within 15 km of Ostrava OpenStreetMap lists 10 garden centres, 1 farm-supply shop, 3 markets and 1 farm shop (collected 28 October 2026).

Artykuły ogrodnicze — garden centre
12 km
Jiří Ostárek — garden centre
15 km
Bon Lait - Kozí farma — farm supply
10 km · bonlait.cz
Targowisko Zabełków — market
14 km · targowiskozabelkow.pl

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.

Questions