Growing Season: Stora Höga
Stenungsund, Västra Götaland, Sweden
Growing season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
10 Apr
Daylight
10+ h
14+ h
10+ h
27 Feb
14 Apr
29 Aug
15 Oct
230 days
Frost-free
10% frost-free
1 May
13 Oct
90% frost risk
165 days
Effective
1 May
13 Oct
165 days
The growing season in Stora Höga is approximately 165 days and is limited by frost.
Last spring frost
The last spring frost normally occurs on 1 May in Stora Höga. At the earliest, the last frost is over around 15 Apr and at the latest around 10 May.
| Frost-free probabilityFrost-free prob. | Date | Grower's risk level | Explanation |
|---|---|---|---|
| 10% | 15 Apr | High risk | Frost 9 out of 10 years after this date |
| 25% | 23 Apr | Frost 3 out of 4 years after this date | |
| 50% | 1 May | Normal risk | Frost every other year after this date |
| 75% | 4 May | Frost 1 out of 4 years after this date | |
| 90% | 10 May | Low risk | Frost 1 out of 10 years after this date |
Growing is often planned around the date when there is a 50% probability that the last spring frost has occurred. In Stora Höga that is 1 May. If you want lower frost risk, choose 75% or 90%, i.e. a later date.
First autumn frost
The first autumn frost normally occurs on 13 Oct in Stora Höga. At the earliest, frost can arrive around 3 Oct and at the latest around 19 Nov.
| Frost probabilityFrost prob. | Date | Grower's risk level | Explanation |
|---|---|---|---|
| 10% | 3 Oct | Low risk | Frost 1 out of 10 years on or before this date |
| 25% | 11 Oct | Frost 1 out of 4 years on or before this date | |
| 50% | 13 Oct | Normal risk | Frost every other year on or before this date |
| 75% | 31 Oct | Frost 3 out of 4 years on or before this date | |
| 90% | 19 Nov | High risk | Frost 9 out of 10 years on or before this date |
Growing is often planned around the date when there is a 50% probability that the first autumn frost has occurred. In Stora Höga that is 13 Oct. If you want lower frost risk, choose 10% or 25%, i.e. an earlier date.
Daylight & Persephone Period
Plants need at least 10 hours of daylight to grow actively. The period with under 10 h is called the Persephone period.
| From | To | Number of days | |
|---|---|---|---|
| Daylight over 10 h | 27 Feb | 15 Oct | 230 |
| Persephone period | 16 Oct | 26 Feb | 135 |
Plan the year's last sowing of cold-hardy plants in Stora Höga so they are approximately 75% mature by 16 Oct when daylight drops below 10 h and growth starts to slow.
Daylight periods
Long-day plants like lettuce, spinach and coriander bolt when daylight gets too long. Plan sowing and harvest during periods when daylight is shorter (10-14 h). Early spring or late summer sowing gives the best results.
| Season | Light | Period | Days | Advice |
|---|---|---|---|---|
| Shorter daylight | 10-14 h | 27 Feb – 13 Apr | 46 | Grow long-day plants like spinach, lettuce and coriander. |
| Longer daylight | 14+ h | 14 Apr – 28 Aug | 137 | High risk of bolting |
| Shorter daylight | 10-14 h | 29 Aug – 15 Oct | 48 | Grow long-day plants |