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Growing season

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 9 May
Daylight
10+ h
14+ h
10+ h
3 Mar
10 Apr
2 Sep
11 Oct
222 days
Frost-free
10% frost-free
9 May
9 Oct
90% frost risk
153 days
Effective
9 May
9 Oct
153 days

The growing season in Skullerstabölen is approximately 153 days and is limited by frost.

Last spring frost

The last spring frost normally occurs on 9 May in Skullerstabölen. At the earliest, the last frost is over around 2 May and at the latest around 18 May.

Frost-free probabilityFrost-free prob. Date Grower's risk level Explanation
10% 2 May High risk Frost 9 out of 10 years after this date
25% 6 May Frost 3 out of 4 years after this date
50% 9 May Normal risk Frost every other year after this date
75% 13 May Frost 1 out of 4 years after this date
90% 18 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 Skullerstabölen that is 9 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 9 Oct in Skullerstabölen. At the earliest, frost can arrive around 27 Sep and at the latest around 19 Oct.

Frost probabilityFrost prob. Date Grower's risk level Explanation
10% 27 Sep Low risk Frost 1 out of 10 years on or before this date
25% 1 Oct Frost 1 out of 4 years on or before this date
50% 9 Oct Normal risk Frost every other year on or before this date
75% 15 Oct Frost 3 out of 4 years on or before this date
90% 19 Oct 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 Skullerstabölen that is 9 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 3 Mar 11 Oct 222
Persephone period 12 Oct 2 Mar 143
Plan the year's last sowing of cold-hardy plants in Skullerstabölen so they are approximately 75% mature by 12 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 3 Mar – 9 Apr 38 Grow long-day plants like spinach, lettuce and coriander.
Longer daylight 14+ h 10 Apr – 1 Sep 145 High risk of bolting
Shorter daylight 10-14 h 2 Sep – 11 Oct 40 Grow long-day plants