When to plant tomatoes in Niigata: 5 May – 30 August

In Niigata, tomato: sow for seedlings from 21 February to 9 July; plant into a greenhouse from 14 April to 30 August; plant out into open ground from 5 May to 30 August.

Tomato in Niigata: soil, season and weather

In Niigata the soil, not frost, sets the date: the last frost is over around 8 March, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 5 May, 58 days later.

Last spring frost	8 March
Top 7 cm of soil at 15 °C	5 May, 58 days after the last frost
Into an unheated greenhouse	14 April – 30 August; April outside: 7.8 °C at night, 15.2 °C by day; card 16–27 °C
First autumn frost	20 December, 229 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	14 July – 8 November
Days left for picking	159
Daylight	11:52 on 14 March, 13:53 on 5 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, May, has 13 rainy days

Tomato in Niigata: care after planting

Planted on 5 May: in the first weeks water every 4 days.

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

5 May — feed: balanced (NPK)
2 June — 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 Niigata during the tomato season

Days average above the tomato card's 16–27 °C in July (28.3 °C) and August (29.9 °C). Months that stay below 16 °C even by day on average: November (14.3 °C) and December (8.4 °C). Nights average below 16 °C in May and October–December (3.8–14.3 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	20.7	13	119	13	14:12
June	24.1	17.9	137	12	14:47
July	28.3	22.9	219	14	14:33
August	29.9	24.2	211	14	13:39
September	26.3	20.7	190	15	12:28
October	19.9	14.3	163	15	11:16
November	14.3	8.7	168	19	10:09
December	8.4	3.8	259	26	9:33

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around Niigata, Tokyo is 31 days earlier and Sendai 8 days later.

City	Distance	Date	Difference
Sendai	165 km	13 May – 3 August	8 days later
Tokyo	255 km	4 April – 24 August	31 days earlier
Nagoya	360 km	12 April – 20 August	23 days earlier
Hamamatsu	376 km	5 April – 28 August	30 days earlier
Kyoto	436 km	21 April – 17 August	14 days earlier
Osaka	479 km	15 April – 27 August	20 days earlier

Where to buy tomato plants and seeds near Niigata

Buy plants ready to set out from 5 May to 30 August (from 14 April to 30 August for an unheated greenhouse); seed for raising your own is sown from 21 February to 9 July. Within 15 km of Niigata OpenStreetMap lists 4 garden centres, 4 markets and 2 farm shops (collected 28 October 2026).

ガーデンセンター — garden centre
6 km
とんとん — garden centre
14 km
GARDENS　GARDEN　新潟西 — garden centre
4 km
コメリPRO牡丹山店 — garden centre
5 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