When to plant watermelons in Kagoshima: 6 May – 16 September

In Kagoshima, watermelon: sow for seedlings from 18 March to 19 August; plant into a greenhouse from 15 April to 16 September; plant out into open ground from 6 May to 16 September.

Watermelon in Kagoshima: soil, season and weather

In Kagoshima the soil, not frost, sets the date: the last frost is over around 24 January, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 6 May, 102 days later.

Last spring frost	24 January
Top 7 cm of soil at 18 °C	6 May, 102 days after the last frost
Into an unheated greenhouse	15 April – 16 September; April outside: 12.7 °C at night, 20.1 °C by day; card 18–35 °C
First autumn frost	26 December, 234 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	4 July – 14 November
Days left for picking	175
Daylight	12:43 on 8 April, 13:32 on 6 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, December, has 9 rainy days

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

Watermelon in Kagoshima: care after planting

Planted on 6 May: in the first weeks water every 5 days.

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

6 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 Kagoshima during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, August, averages 30.8 °C. Months that stay below 18 °C even by day on average: December (13.1 °C). Nights average below 18 °C in May and October–December (6.6–17.7 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	23.4	16.4	285	14	13:45
June	26.2	20.4	502	20	14:12
July	29.7	24.1	374	21	14:01
August	30.8	24.8	228	18	13:20
September	28.8	22.8	236	16	12:23
October	24.3	17.7	146	11	11:26
November	19	12.2	125	9	10:34
December	13.1	6.6	76	9	10:06

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Kagoshima, Kumamoto is 4 days earlier and Hiroshima 20 days later.

City	Distance	Date	Difference
Kumamoto	134 km	2 May – 24 August	4 days earlier
Fukuoka	222 km	5 May – 11 September	1 day earlier
Kitakyushu	255 km	from 15 May	9 days later
Hiroshima	357 km	26 May – 16 August	20 days later
Busan	421 km	15 May – 13 August	9 days later
Jeju City	434 km	6 May – 9 September	same day

Where to buy watermelon plants and seeds near Kagoshima

Buy plants ready to set out from 6 May to 16 September (from 15 April to 16 September for an unheated greenhouse); seed for raising your own is sown from 18 March to 19 August. Within 15 km of Kagoshima OpenStreetMap lists 4 garden centres, 1 farm-supply shop, 5 markets and 7 farm shops (collected 28 October 2026).

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