Greenly Garden

When to plant zucchini in Swansea: 21 June – 14 September

In Swansea, zucchini: sow for seedlings from 10 May to 24 August; plant into a greenhouse from 31 May to 14 September; plant out into open ground from 21 June to 14 September.

Zucchini 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 18 °C — the minimum on the zucchini card — only around 21 June, 113 days later.

Last spring frost28 February
Top 7 cm of soil at 18 °C21 June, 113 days after the last frost
First autumn frost1 December, 163 days after the start
Days in the bed to the first harvest (card)36
First harvest, if planted in this window27 July – 20 October
Days left for picking127
Daylight16:17 on 31 May, 16:40 on 21 June
Watering outdoors when fruiting (card)every 3 days; the driest month, June, has 16 rainy days

The same dates in Swansea hold for Cucumber, Bell Pepper, Eggplant, Pumpkin and Watermelon.

Zucchini in Swansea: care after planting

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

Pests and diseases of zucchini to watch for:

Weather in Swansea during the zucchini season

About 1090 mm of rain falls in the season; June is the driest month (101 mm) and December the wettest (203 mm).

MonthDay, °CNight, °CRain, mmRainy daysDaylight on the 15th
June18.312.41011616:38
July19.713.91171616:13
August19.414.11391814:40
September17.812.51681612:43
October14.710.21871810:45
November11.26.8175188:53
December9.45.6203197:51

ERA5 2016–2025, Open-Meteo

Zucchini in nearby cities

Around Swansea, Bristol is 2 days earlier and Plymouth 26 days later.

CityDistanceDateDifference
Cardiff55 km24 June – 5 September3 days later
Bristol95 km19 June – 5 September2 days earlier
Exeter104 km23 June – 10 September2 days later
Worcester134 km19 June – 5 September2 days earlier
Plymouth140 km17 July – 14 September26 days later
Birmingham170 km20 June – 2 September1 day earlier

Where to buy zucchini plants and seeds near Swansea

Buy plants ready to set out from 21 June to 14 September (from 31 May to 14 September for an unheated greenhouse); seed for raising your own is sown from 10 May to 24 August. Within 15 km of Swansea OpenStreetMap lists 1 garden centre, 2 markets and 1 farm shop (collected 20 October 2026).

Places: © OpenStreetMap contributors, ODbL.

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

When to plant zucchini in Swansea?

In Swansea, zucchini: sow for seedlings from 10 May to 24 August; plant into a greenhouse from 31 May to 14 September; plant out into open ground from 21 June to 14 September.

When to sow zucchini for seedlings in Swansea?

Sow for seedlings from 10 May to 24 August.

When is the last spring frost in Swansea?

Last spring frost around 28 February, first autumn frost around 1 December.

Other crops in Swansea, with their dates