When to plant tomatoes in Okayama: 21 April – 25 August

In Okayama, tomato: sow for seedlings from 7 February to 4 July; plant into a greenhouse from 31 March to 25 August; plant out into open ground from 21 April to 25 August. For plants and seeds, the places nearby include 瀬戸内庭園資材 (garden centre, 12 km) and 清光園芸 (garden centre, 12 km); addresses and opening hours are below.

Tomato in Okayama: soil, season and weather

In Okayama the soil, not frost, sets the date: the last frost is over around 20 March, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 21 April, 32 days later.

Last spring frost	20 March
Top 7 cm of soil at 15 °C	21 April, 32 days after the last frost
Into an unheated greenhouse	31 March – 25 August; March outside: 4.3 °C at night, 14.3 °C by day; card 16–27 °C
First autumn frost	15 December, 238 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	30 June – 3 November
Days left for picking	168
Daylight	11:23 on 28 February, 13:15 on 21 April
Watering outdoors when fruiting (card)	every 3 days; the driest month, December, has 5 rainy days

Tomato in Okayama: care after planting

Planted on 21 April: in the first weeks water every 4 days.

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

21 April — feed: balanced (NPK)
19 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 Okayama during the tomato season

Days average above the tomato card's 16–27 °C in July (30.5 °C), August (32.4 °C) and September (28.3 °C). Months that stay below 16 °C even by day on average: December (10.8 °C). Nights average below 16 °C in April, May and October–December (2.3–14.2 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
April	19.1	9	135	10	13:02
May	23.4	13.6	133	10	13:58
June	26.7	18.3	208	14	14:28
July	30.5	23.1	230	15	14:16
August	32.4	24.2	162	13	13:29
September	28.3	20.8	193	14	12:26
October	22.4	14.2	115	10	11:21
November	16.7	7.7	54	6	10:22
December	10.8	2.3	37	5	9:51

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around Okayama, Fukuoka is 14 days earlier and Hiroshima 14 days later.

City	Distance	Date	Difference
Hiroshima	138 km	5 May – 5 August	14 days later
Osaka	145 km	15 April – 27 August	6 days earlier
Kyoto	174 km	21 April – 17 August	same day
Nagoya	278 km	12 April – 20 August	9 days earlier
Kitakyushu	292 km	from 14 April	7 days earlier
Fukuoka	345 km	7 April – 31 August	14 days earlier

Where to buy tomato plants and seeds near Okayama

Buy plants ready to set out from 21 April to 25 August (from 31 March to 25 August for an unheated greenhouse); seed for raising your own is sown from 7 February to 4 July. Within 15 km of Okayama OpenStreetMap lists 8 garden centres, 5 farm-supply shops, 3 markets and 19 farm shops (collected 28 October 2026).

清光園芸 — garden centre
Apr–Sept: 09:00–18:30; Oct–Mar: 09:00–18:00 · 12 km · seiko-engei.com
高原農芸 — garden centre
08:30–18:30; Tue closed · 15 km · hanatoyasai.com
瀬戸内庭園資材 — garden centre
09:30–18:00 · 12 km · ameblo.jp
倉敷路地市庭 — market
Sat 09:00–13:00 · 15 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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