When to plant tomatoes in Osaka: 15 April – 27 August

In Osaka, tomato: sow for seedlings from 1 February to 6 July; plant into a greenhouse from 25 March to 27 August; plant out into open ground from 15 April to 27 August. For plants and seeds, the places nearby include 大和肥料株式会社 (farm supply, 7 km) and 花しきぶ (garden centre, 13 km); addresses and opening hours are below.

Tomato in Osaka: soil, season and weather

In Osaka the soil, not frost, sets the date: the last frost is over around 14 March, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 15 April, 32 days later.

Last spring frost	14 March
Top 7 cm of soil at 15 °C	15 April, 32 days after the last frost
Into an unheated greenhouse	25 March – 27 August; March outside: 4.9 °C at night, 13.7 °C by day; card 16–27 °C
First autumn frost	17 December, 246 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	24 June – 5 November
Days left for picking	176
Daylight	11:10 on 22 February, 13:02 on 15 April
Watering outdoors when fruiting (card)	every 3 days; the driest month, December, has 6 rainy days

Tomato in Osaka: care after planting

Planted on 15 April: in the first weeks water every 4 days.

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

15 April — feed: balanced (NPK)
13 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 Osaka during the tomato season

Days average above the tomato card's 16–27 °C in July (30.8 °C), August (32.5 °C) and September (28.9 °C). Months that stay below 16 °C even by day on average: December (11.1 °C). Nights average below 16 °C in April, May and October–December (2.8–14.7 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
April	18.7	9.8	148	10	13:02
May	23	14.5	189	10	13:58
June	26.5	19.1	244	14	14:28
July	30.8	23.9	240	15	14:16
August	32.5	25.1	173	14	13:29
September	28.9	21.7	209	14	12:26
October	22.5	14.7	188	11	11:21
November	16.8	8.3	72	7	10:22
December	11.1	2.8	49	6	9:51

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around Osaka, Tokyo is 11 days earlier and Hiroshima 20 days later.

City	Distance	Date	Difference
Kyoto	43 km	21 April – 17 August	6 days later
Nagoya	139 km	12 April – 20 August	3 days earlier
Okayama	145 km	21 April – 25 August	6 days later
Hamamatsu	204 km	5 April – 28 August	10 days earlier
Hiroshima	281 km	5 May – 5 August	20 days later
Tokyo	397 km	4 April – 24 August	11 days earlier

Where to buy tomato plants and seeds near Osaka

Buy plants ready to set out from 15 April to 27 August (from 25 March to 27 August for an unheated greenhouse); seed for raising your own is sown from 1 February to 6 July. Within 15 km of Osaka OpenStreetMap lists 16 garden centres, 4 farm-supply shops, 3 plant nurseries, 19 markets and 8 farm shops (collected 28 October 2026).

花しきぶ — garden centre
Mon–Tue, Thu–Sun 09:30–18:00 · 13 km
大和肥料株式会社 — farm supply
Sat 10:00–16:00; Sun 10:00–12:00 · 7 km · daiwa-ism.com
Kuromon Ichiba Market — market
Sun closed · 3 km · kuromon.com
宝来市場 — market
Mon–Wed 10:00–19:00; Fri–Sun 10:00–19:00 · 6 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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