When to plant watermelons in Kostanay: 30 May – 23 June

In Kostanay, watermelon: sow for seedlings from 11 April to 26 May; plant into a greenhouse from 9 May to 23 June; plant out into open ground from 30 May to 23 June.

Watermelon in Kostanay: soil, season and weather

In Kostanay the soil, not frost, sets the date: the last frost is over around 4 May, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 30 May, 26 days later.

Last spring frost	4 May
Top 7 cm of soil at 18 °C	30 May, 26 days after the last frost
Into an unheated greenhouse	9 May – 23 June; May outside: 6.9 °C at night, 20.4 °C by day; card 18–35 °C
First autumn frost	2 October, 125 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	28 July – 21 August
Days left for picking	66
Daylight	15:04 on 2 May, 16:32 on 30 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, October, has 8 rainy days

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

Watermelon in Kostanay: care after planting

Planted on 30 May: in the first weeks water every 5 days.

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

30 May — 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 Kostanay during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 26.2 °C. Months that stay below 18 °C even by day on average: September (17.3 °C) and October (8.9 °C). Nights average below 18 °C in every month of the season, from 0.3 °C to 15.3 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	20.4	6.9	48	8	15:50
June	23.9	12.4	51	8	16:56
July	26.2	15.3	60	10	16:30
August	24.7	13.5	51	8	14:50
September	17.3	7.1	37	7	12:45
October	8.9	0.3	36	8	10:40

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

All the nearest cities on our list plant watermelon later than Kostanay; the closest date is in Chelyabinsk, 1 day later.

City	Distance	Date	Difference
Chelyabinsk	261 km	31 May – 25 June	1 day later
Kurgan	273 km	1 June – 22 June	2 days later
Magnitogorsk	307 km	2 June – 17 June	3 days later
Kokshetau	384 km	1 June – 20 June	2 days later
Petropavl	405 km	7 June – 20 June	8 days later
Yekaterinburg	447 km	15 June – 19 June	16 days later

Where to buy watermelon plants and seeds near Kostanay

Buy plants ready to set out from 30 May to 23 June (from 9 May to 23 June for an unheated greenhouse); seed for raising your own is sown from 11 April to 26 May. Within 15 km of Kostanay OpenStreetMap lists 3 garden centres, 10 markets and 1 farm shop (collected 27 October 2026).

Центральный Рынок — market
2 km
рынок — market
3 km
Рынок Емшан — market
4 km
Рынок — market
5 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.

Questions