When to plant watermelons in Kostroma: 18 June – 2 July

In Kostroma, watermelon: sow for seedlings from 30 April to 4 June; plant into a greenhouse from 28 May to 2 July; plant out into open ground from 18 June to 2 July. For plants and seeds, the places nearby include Десяточка экспресс (farm shop, 2 km); addresses and opening hours are below.

Watermelon in Kostroma: soil, season and weather

In Kostroma the soil, not frost, sets the date: the last frost is over around 6 May, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 18 June, 43 days later. 115 days separate planting out (18 June) from the first autumn frost (11 October); the card's 59 days to the first harvest leave 56 for picking, so a start 8 weeks late would still fit.

Last spring frost	6 May
Top 7 cm of soil at 18 °C	18 June, 43 days after the last frost
Into an unheated greenhouse	28 May – 2 July; May outside: 5.8 °C at night, 16.3 °C by day; card 18–35 °C
First autumn frost	11 October, 115 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	16 August – 30 August
Days left for picking	56
Daylight	17:01 on 21 May, 18:06 on 18 June
Watering outdoors when fruiting (card)	every 5 days; the driest month, September, has 11 rainy days

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

Watermelon in Kostroma: care after planting

Planted on 18 June: in the first weeks water every 5 days.

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

18 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 Kostroma during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 23.4 °C. Months that stay below 18 °C even by day on average: September (15.6 °C) and October (8 °C). Nights average below 18 °C in every month of the season, from 2.4 °C to 14.1 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
June	20.8	11	78	12	18:04
July	23.4	14.1	82	14	17:28
August	21.9	12.6	63	11	15:23
September	15.6	7.8	56	11	12:53
October	8	2.4	63	14	10:25

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Kostroma, Nizhny Novgorod is 16 days earlier and Vologda 4 days later.

City	Distance	Date	Difference
Yaroslavl	65 km	15 June – 1 July	3 days earlier
Ivanovo	86 km	15 June – 2 July	3 days earlier
Vologda	172 km	22 June – 1 July	4 days later
Vladimir	184 km	13 June – 6 July	5 days earlier
Cherepovets	232 km	22 June – 8 July	4 days later
Nizhny Novgorod	245 km	2 June – 9 July	16 days earlier

Where to buy watermelon plants and seeds near Kostroma

Buy plants ready to set out from 18 June to 2 July (from 28 May to 2 July for an unheated greenhouse); seed for raising your own is sown from 30 April to 4 June. Within 15 km of Kostroma OpenStreetMap lists 2 garden centres, 2 markets and 1 farm shop (collected 27 October 2026).

Ярмарка на Островского — market
1 km
Ярмарка Купеческое подворье — market
Mon–Sun 09:00–21:00 · 2 km
Десяточка экспресс — farm shop
Московская улица 19, 156001 Кострома · Mon–Sun 08:00–22:00 · 2 km
Сияние — garden centre
0 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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