When to plant watermelons in Jeonju: 19 May – 8 August

In Jeonju, watermelon: sow for seedlings from 31 March to 11 July; plant into a greenhouse from 28 April to 8 August; plant out into open ground from 19 May to 8 August.

Watermelon in Jeonju: soil, season and weather

In Jeonju the soil, not frost, sets the date: the last frost is over around 27 March, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 19 May, 53 days later.

Last spring frost	27 March
Top 7 cm of soil at 18 °C	19 May, 53 days after the last frost
Into an unheated greenhouse	28 April – 8 August; April outside: 7.3 °C at night, 17.9 °C by day; card 18–35 °C
First autumn frost	17 November, 182 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	17 July – 6 October
Days left for picking	123
Daylight	13:18 on 21 April, 14:09 on 19 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, November, has 7 rainy days

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

Watermelon in Jeonju: care after planting

Planted on 19 May: in the first weeks water every 5 days.

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

19 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 Jeonju during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, August, averages 29.5 °C. Months that stay below 18 °C even by day on average: November (12.3 °C). Nights average below 18 °C in May, June and September–November (3.5–17.6 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	22.3	12	106	10	14:03
June	26.3	17.1	150	13	14:34
July	28.7	21.7	267	19	14:22
August	29.5	22.1	232	18	13:32
September	25.4	17.6	178	12	12:26
October	19	10.4	85	8	11:19
November	12.3	3.5	55	7	10:18

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

All the nearest cities on our list plant watermelon earlier than Jeonju; the closest date is in Ulsan, 1 day earlier.

City	Distance	Date	Difference
Daejeon	63 km	17 May – 3 August	2 days earlier
Gwangju	77 km	17 May – 14 August	2 days earlier
Daegu	131 km	16 May – 12 August	3 days earlier
Busan	188 km	15 May – 13 August	4 days earlier
Seoul	194 km	15 May – 28 July	4 days earlier
Ulsan	198 km	18 May – 7 August	1 day earlier

Where to buy watermelon plants and seeds near Jeonju

Buy plants ready to set out from 19 May to 8 August (from 28 April to 8 August for an unheated greenhouse); seed for raising your own is sown from 31 March to 11 July. Within 15 km of Jeonju OpenStreetMap lists 7 markets (collected 28 October 2026).

Samnye Traditional Market — market
12 km
봉동생강골시장 — market
13 km
서신동 시장 — market
3 km
이서중앙정미소 — market
12 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