When to plant tomatoes in Jeju City: 11 April – 29 August

In Jeju City, tomato: sow for seedlings from 28 January to 8 July; plant into a greenhouse from 21 March to 29 August; plant out into open ground from 11 April to 29 August.

Tomato in Jeju City: soil, season and weather

In Jeju City the soil, not frost, sets the date: the last frost is over around 18 February, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 11 April, 52 days later.

Last spring frost	18 February
Top 7 cm of soil at 15 °C	11 April, 52 days after the last frost
Into an unheated greenhouse	21 March – 29 August; March outside: 7.3 °C at night, 13.3 °C by day; card 16–27 °C
First autumn frost	19 December, 252 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	20 June – 7 November
Days left for picking	182
Daylight	11:05 on 18 February, 12:52 on 11 April
Watering outdoors when fruiting (card)	every 3 days; the driest month, December, has 14 rainy days

Tomato in Jeju City: care after planting

Planted on 11 April: in the first weeks water every 4 days.

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

11 April — feed: balanced (NPK)
9 May — feed: nitrogen

Pests and diseases of tomato 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 Jeju City during the tomato season

Days average above the tomato card's 16–27 °C in July (29 °C) and August (29.9 °C). Months that stay below 16 °C even by day on average: November (15.7 °C) and December (9.9 °C). Nights average below 16 °C in April, May and November, December (5.2–15.7 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
April	17.6	11.4	134	10	13:00
May	21.8	15.7	148	11	13:53
June	25	19.9	208	14	14:22
July	29	24.6	233	18	14:10
August	29.9	25.4	240	19	13:25
September	26.1	22	354	19	12:25
October	20.8	16.4	182	13	11:23
November	15.7	10.4	108	11	10:27
December	9.9	5.2	85	14	9:57

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

All the nearest cities on our list plant tomato later than Jeju City; the closest date is in Busan, 10 days later.

City	Distance	Date	Difference
Gwangju	187 km	24 April – 3 August	13 days later
Jeonju	263 km	25 April – 28 July	14 days later
Busan	299 km	21 April – 2 August	10 days later
Daegu	324 km	22 April – 1 August	11 days later
Daejeon	326 km	24 April – 23 July	13 days later
Ulsan	342 km	22 April – 27 July	11 days later

Where to buy tomato plants and seeds near Jeju City

Buy plants ready to set out from 11 April to 29 August (from 21 March to 29 August for an unheated greenhouse); seed for raising your own is sown from 28 January to 8 July. Within 15 km of Jeju City OpenStreetMap lists 1 garden centre, 7 markets and 1 farm shop (collected 28 October 2026).

Well Being Wonye Mart — garden centre
3 km
Dongmun Market — market
1 km
골목시장 — market
1 km
제주시 민속오일시장 — market
4 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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