When to plant tomatoes in Southampton: 23 May – 3 August

In Southampton, tomato: sow for seedlings from 11 March to 12 June; plant into a greenhouse from 2 May to 3 August; plant out into open ground from 23 May to 3 August. For plants and seeds, the places nearby include Greenhouse People (garden centre, 5 km) and The Garden Society (garden centre, 8 km); addresses and opening hours are below.

Tomato in Southampton: soil, season and weather

In Southampton the soil, not frost, sets the date: the last frost is over around 4 April, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 23 May, 49 days later.

Last spring frost	4 April
Top 7 cm of soil at 15 °C	23 May, 49 days after the last frost
Into an unheated greenhouse	2 May – 3 August; May outside: 8.2 °C at night, 17.4 °C by day; card 16–27 °C
First autumn frost	23 November, 184 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	1 August – 12 October
Days left for picking	114
Daylight	12:54 on 1 April, 15:52 on 23 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, July, has 10 rainy days

Tomato in Southampton: care after planting

Planted on 23 May: in the first weeks water every 4 days.

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

23 May — feed: balanced (NPK)
20 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 Southampton during the tomato season

No month of the season averages above the tomato card's 16–27 °C by day; the warmest, July, averages 22.3 °C. Months that stay below 16 °C even by day on average: October (15.4 °C) and November (11.1 °C). Nights average below 16 °C in every month of the season, from 5.2 °C to 13.5 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	17.4	8.2	62	11	15:30
June	20.5	11.5	59	11	16:30
July	22.3	13.5	54	10	16:06
August	21.8	13.3	60	10	14:36
September	19.2	11.2	73	11	12:42
October	15.4	8.8	100	13	10:47
November	11.1	5.2	86	13	8:58

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around Southampton, Portsmouth is 2 days earlier and Brighton 26 days later.

City	Distance	Date	Difference
Portsmouth	24 km	21 May – 11 August	2 days earlier
Brighton	89 km	18 June – 11 August	26 days later
Oxford	95 km	26 May – 3 August	3 days later
Bristol	103 km	28 May – 2 August	5 days later
London	111 km	24 May – 3 August	1 day later
Cardiff	140 km	26 May – 2 August	3 days later

Where to buy tomato plants and seeds near Southampton

Buy plants ready to set out from 23 May to 3 August (from 2 May to 3 August for an unheated greenhouse); seed for raising your own is sown from 11 March to 12 June. Within 15 km of Southampton OpenStreetMap lists 28 garden centres, 15 plant nurseries, 1 market and 10 farm shops (collected 20 October 2026).

The Garden Society — garden centre
Allington Lane, SO50 7DE Southampton · Mon–Sat 09:00–17:30; Sun 10:00–16:30 · 8 km · thegardensociety.co.uk
Dobbies Garden Centre — garden centre
Southampton Road, SO40 2NB · Mon–Sat 09:00–18:00; Sun 10:30–16:30 · 12 km · dobbies.com
Mole Country Store — garden centre
Alma Road, SO51 8ED Romsey · Mon–Sat 08:30–17:30; Sun 10:00–16:00 · 12 km · molecountrystores.co.uk
Greenhouse People — garden centre
Mansbridge Road, SO18 3HW Southampton · Mon–Sat 09:00–18:00; Sun 10:30–16:30 · 5 km · greenhousepeople.co.uk

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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