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Growing season

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 10 May
Daylight
10+ h
14+ h
10+ h
1 Mar
12 Apr
1 Sep
12 Oct
225 days
Frost-free
10% frost-free
4 May
18 Oct
90% frost risk
167 days
Effective
4 May
12 Oct
161 days

The growing season in Kultebo is approximately 161 days and is limited by both frost and daylight.

Last spring frost

The last spring frost normally occurs on 4 May in Kultebo. At the earliest, the last frost is over around 26 Apr and at the latest around 11 May.

Frost-free probabilityFrost-free prob. Date Grower's risk level Explanation
10% 26 Apr High risk Frost 9 out of 10 years after this date
25% 30 Apr Frost 3 out of 4 years after this date
50% 4 May Normal risk Frost every other year after this date
75% 7 May Frost 1 out of 4 years after this date
90% 11 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 Kultebo that is 4 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 18 Oct in Kultebo. At the earliest, frost can arrive around 4 Oct and at the latest around 31 Oct.

Frost probabilityFrost prob. Date Grower's risk level Explanation
10% 4 Oct Low risk Frost 1 out of 10 years on or before this date
25% 10 Oct Frost 1 out of 4 years on or before this date
50% 18 Oct Normal risk Frost every other year on or before this date
75% 25 Oct Frost 3 out of 4 years on or before this date
90% 31 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 Kultebo that is 18 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 1 Mar 12 Oct 225
Persephone period 13 Oct 28 Feb 140
Plan the year's last sowing of cold-hardy plants in Kultebo so they are approximately 75% mature by 13 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 1 Mar – 11 Apr 42 Grow long-day plants like spinach, lettuce and coriander.
Longer daylight 14+ h 12 Apr – 31 Aug 142 High risk of bolting
Shorter daylight 10-14 h 1 Sep – 12 Oct 42 Grow long-day plants