Hortuli

Search for your location to see a personalised planting calendar, frost dates and more.

Log in
Svenska
English
Dansk
Flottskär
Create your calendar
Create your calendar

Growing Season: Flottskär

Tierp, Uppsala, Sweden
No frost in sight Last frost normally in 2 days (5 May), but frost-free in the forecast.

Growing season

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 3 May
Daylight
10+ h
14+ h
10+ h
1 Mar
12 Apr
31 Aug
13 Oct
226 days
Frost-free
10% frost-free
5 May
11 Oct
90% frost risk
159 days
Effective
5 May
11 Oct
159 days

The growing season in Flottskär is approximately 159 days and is limited by frost.

Last spring frost

The last spring frost normally occurs on 5 May in Flottskär. At the earliest, the last frost is over around 25 Apr and at the latest around 13 May.

Frost-free probabilityFrost-free prob. Date Grower's risk level Explanation
10% 25 Apr High risk Frost 9 out of 10 years after this date
25% 1 May Frost 3 out of 4 years after this date
50% 5 May Normal risk Frost every other year after this date
75% 9 May Frost 1 out of 4 years after this date
90% 13 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 Flottskär that is 5 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 11 Oct in Flottskär. At the earliest, frost can arrive around 28 Sep and at the latest around 21 Oct.

Frost probabilityFrost prob. Date Grower's risk level Explanation
10% 28 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% 11 Oct Normal risk Frost every other year on or before this date
75% 17 Oct Frost 3 out of 4 years on or before this date
90% 21 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 Flottskär that is 11 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 13 Oct 226
Persephone period 14 Oct 28 Feb 139
Plan the year's last sowing of cold-hardy plants in Flottskär so they are approximately 75% mature by 14 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 – 30 Aug 141 High risk of bolting
Shorter daylight 10-14 h 31 Aug – 13 Oct 44 Grow long-day plants