When to plant tomatoes in Swansea: 24 May – 11 August

In Swansea, tomato: sow for seedlings from 12 March to 20 June; plant into a greenhouse from 3 May to 11 August; plant out into open ground from 24 May to 11 August.

Tomato in Swansea: soil, season and weather

In Swansea the soil, not frost, sets the date: the last frost is over around 28 February, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 24 May, 85 days later.

Last spring frost	28 February
Top 7 cm of soil at 15 °C	24 May, 85 days after the last frost
Into an unheated greenhouse	3 May – 11 August; May outside: 9.4 °C at night, 16 °C by day; card 16–27 °C
First autumn frost	1 December, 191 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	2 August – 20 October
Days left for picking	121
Daylight	13:00 on 2 April, 16:01 on 24 May
Watering outdoors when fruiting (card)	every 3 days; the driest month, May, has 13 rainy days

Tomato in Swansea: care after planting

Planted on 24 May: in the first weeks water every 4 days.

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

24 May — feed: balanced (NPK)
21 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 Swansea during the tomato season

No month of the season averages above the tomato card's 16–27 °C by day; the warmest, July, averages 19.7 °C. Months that stay below 16 °C even by day on average: October (14.7 °C), November (11.2 °C) and December (9.4 °C). Nights average below 16 °C in every month of the season, from 5.6 °C to 14.1 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	16	9.4	92	13	15:36
June	18.3	12.4	101	16	16:38
July	19.7	13.9	117	16	16:13
August	19.4	14.1	139	18	14:40
September	17.8	12.5	168	16	12:43
October	14.7	10.2	187	18	10:45
November	11.2	6.8	175	18	8:53
December	9.4	5.6	203	19	7:51

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

All the nearest cities on our list plant tomato later than Swansea; the closest date is in Birmingham, 1 day later.

City	Distance	Date	Difference
Cardiff	55 km	26 May – 2 August	2 days later
Bristol	95 km	28 May – 2 August	4 days later
Exeter	104 km	1 June – 7 August	8 days later
Worcester	134 km	1 June – 2 August	8 days later
Plymouth	140 km	21 June – 11 August	28 days later
Birmingham	170 km	25 May – 30 July	1 day later

Where to buy tomato plants and seeds near Swansea

Buy plants ready to set out from 24 May to 11 August (from 3 May to 11 August for an unheated greenhouse); seed for raising your own is sown from 12 March to 20 June. Within 15 km of Swansea OpenStreetMap lists 1 garden centre, 2 markets and 1 farm shop (collected 20 October 2026).

Pontarddulais Garden Centre — garden centre
11 km
Swansea Market — market
0 km
Neath Indoor Market — market
10 km
Murton Farm Shop — farm shop
8 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