GardenCalc
One page for every city and postcode district in England, Scotland and Wales. Pick a city below or type your postcode, and the page works out your frost dates and a dated sowing table for 15 crops from the Met Office 5 km frost record for your own postcode district. Updated August 2026.
Where are you sowing?
Covers England, Scotland and Wales (2,728 postcode districts). Northern Ireland has no district-level data yet: BT postcodes are pointed to the frost date calculator, which carries the regional figure.
How the 15 cities compare
Sorted by the safe planting-out date. Liverpool is safe first, from 10 Apr; Exeter is last, from 16 May, 36 days (about 5 weeks) later. Frost-free seasons run from 202 days in Exeter to 259 in London. Every figure is the Met Office 5 km record for that city's centre postcode district, 1991 to 2020. Choose a city name to open its full sowing table.
| City | Typical last frost | Safe to plant out (9 years in 10) | Typical first autumn frost | Frost-free days |
|---|---|---|---|---|
| 17 Mar | 10 Apr | 23 Nov | 251 | |
| 20 Mar | 10 Apr | 20 Nov | 245 | |
| 7 Mar | 14 Apr | 21 Nov | 259 | |
| 2 Apr | 21 Apr | 12 Nov | 224 | |
| 30 Mar | 21 Apr | 20 Nov | 235 | |
| 7 Apr | 21 Apr | 15 Nov | 222 | |
| 2 Apr | 27 Apr | 20 Nov | 232 | |
| 10 Apr | 3 May | 10 Nov | 214 | |
| 9 Apr | 6 May | 10 Nov | 215 | |
| 14 Apr | 7 May | 12 Nov | 212 | |
| 16 Apr | 7 May | 6 Nov | 204 | |
| 14 Apr | 9 May | 10 Nov | 210 | |
| 12 Apr | 11 May | 9 Nov | 211 | |
| 10 Apr | 12 May | 8 Nov | 212 | |
| 18 Apr | 16 May | 6 Nov | 202 |
The rules behind every date
The sowing table for any place is worked out from its safe last-frost date using these offsets, taken from the grow guides linked in the last column (RHS, Thompson & Morgan, Sarah Raven and Suttons). They are for outdoor-grown plants; greenhouse crops start earlier. Sow-indoors windows are held to February at the earliest, the earliest month the cited guidance gives.
| Crop | Sow indoors | Sow direct outside | Plant out | Grow guide |
|---|---|---|---|---|
| Tomatoes tender | 8 to 6 weeks before the safe date (never before February) | – | the safe date to 14 days after the safe date | RHS · Thompson & Morgan |
| Potatoes tender | – | 49 days before the safe date to 14 days before the safe date | 49 days before the safe date to 14 days before the safe date | RHS · Thompson & Morgan |
| Runner beans tender | 6 to 3 weeks before the safe date (never before February) | the safe date to 42 days after the safe date | the safe date to 14 days after the safe date | RHS · Thompson & Morgan |
| Sweet peas hardy | 16 to 6 weeks before the safe date (never before February) | 42 days before the safe date to the safe date | 42 days before the safe date to the safe date | RHS · Thompson & Morgan |
| Dahlias tender | 12 to 6 weeks before the safe date (never before February) | 28 days before the safe date to 14 days before the safe date | the safe date to 14 days after the safe date | RHS · Thompson & Morgan |
| Courgettes tender | 6 to 3 weeks before the safe date (never before February) | the safe date to 28 days after the safe date | 7 days after the safe date to 21 days after the safe date | RHS · Thompson & Morgan |
| Cucumbers (outdoor) tender | 5 to 3 weeks before the safe date (never before February) | 7 days after the safe date to 28 days after the safe date | 7 days after the safe date to 21 days after the safe date | RHS · Thompson & Morgan |
| Sunflowers half-hardy | 8 to 4 weeks before the safe date (never before February) | 28 days before the safe date to 14 days after the safe date | the safe date to 14 days after the safe date | RHS · Sarah Raven |
| Pumpkins and winter squash tender | 6 to 3 weeks before the safe date (never before February) | the safe date to 28 days after the safe date | the safe date to 21 days after the safe date | RHS · Thompson & Morgan |
| Sweetcorn tender | 6 to 4 weeks before the safe date (never before February) | the safe date to 21 days after the safe date | the safe date to 21 days after the safe date | RHS · Thompson & Morgan |
| French beans tender | 5 to 2 weeks before the safe date (never before February) | the safe date to 49 days after the safe date | the safe date to 14 days after the safe date | RHS · Suttons |
| Chillies tender | 16 to 8 weeks before the safe date (never before February) | – | 7 days after the safe date to 28 days after the safe date | RHS · Sarah Raven |
| Sweet peppers tender | 10 to 7 weeks before the safe date (never before February) | – | 7 days after the safe date to 28 days after the safe date | RHS · Suttons |
| Basil tender | 8 to 2 weeks before the safe date (never before February) | 14 days after the safe date to 42 days after the safe date | 7 days after the safe date to 28 days after the safe date | RHS · Thompson & Morgan |
| Geraniums and tender bedding half-hardy | – | – | the safe date to 14 days after the safe date | RHS · Sarah Raven |
Build a printable week-by-week plan for your postcode → Full UK planting calendar → Frost dates, ground frost and growing-season length →
Frost and sowing questions
What does “safe to plant out” mean?
The date by which, in 27 of the 30 years from 1991 to 2020 (9 years in 10), the last air frost had already passed. One year in ten it frosts later, so the table also shows the latest frost on record. Plant tender crops after the safe date and keep fleece to hand until then.
Why do the cities differ so much?
Latitude, altitude and distance from the sea. In this set Liverpool is safe first (10 Apr) and Exeter last (16 May), about 5 weeks apart. The autumn side varies less: first frosts run from 6 Nov in Exeter to 23 Nov in Liverpool.
My postcode is not one of the 15 cities. Can I still use this?
Yes. Type your postcode in the box and the same engine reads your own postcode district from the 2,728 in the Met Office dataset. Northern Ireland has no district-level data, so BT postcodes are pointed to the frost date calculator's regional figure.
Are these dates a forecast?
No. They are a 30-year climatology: what usually happens, not what will happen this week. Check the live garden weather forecast before you plant out, and expect a sheltered city garden or an exposed edge-of-town plot to differ from its district by a week or two.
Where these dates come from
Frost dates: Met Office HadUK-Grid v1.3.2 5 km gridded daily minimum temperature (dataset overview), 1991 to 2020, air frost at 0°C, per postcode district (2,728 districts across England, Scotland and Wales; contains public sector information licensed under the Open Government Licence v3.0). "Safe" means 9 years in 10 the last frost had already passed by that date. Ground-frost days by month are observed counts from the same dataset. Limits: a 5 km grid smooths frost hollows, valley bottoms and urban heat islands, so a sheltered city garden or an exposed edge-of-town plot can differ. Sowing offsets: RHS and Thompson & Morgan grow guides, linked per crop above. This page is not a forecast; use the live forecast for tonight.
Guidance, not a guarantee. These dates are climate averages for general information. Your own plot, the season and the plants you buy all vary, so check the live forecast and your seed packet before you sow or plant out, and treat any single date as a starting point rather than a promise.
Frost warnings and sowing reminders
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