Growing Season: Sundbyberg
Growing season
The growing season in Sundbyberg is approximately 166 days and is limited by both frost and daylight.
Last spring frost
The last spring frost normally occurs on 1 May in Sundbyberg. At the earliest, the last frost is over around 9 Apr and at the latest around 13 May.
| Frost-free probabilityFrost-free prob. | Date | Grower's risk level | Explanation |
|---|---|---|---|
| 10% | 9 Apr | High risk | Frost 9 out of 10 years after this date |
| 25% | 19 Apr | Frost 3 out of 4 years after this date | |
| 50% | 1 May | Normal risk | Frost every other year after this date |
| 75% | 7 May | Frost 1 out of 4 years after this date | |
| 90% | 13 May | Low risk | Frost 1 out of 10 years after this date |
First autumn frost
The first autumn frost normally occurs on 26 Oct in Sundbyberg. At the earliest, frost can arrive around 7 Oct and at the latest around 14 Nov.
| Frost probabilityFrost prob. | Date | Grower's risk level | Explanation |
|---|---|---|---|
| 10% | 7 Oct | Low risk | Frost 1 out of 10 years on or before this date |
| 25% | 13 Oct | Frost 1 out of 4 years on or before this date | |
| 50% | 26 Oct | Normal risk | Frost every other year on or before this date |
| 75% | 2 Nov | Frost 3 out of 4 years on or before this date | |
| 90% | 14 Nov | High risk | Frost 9 out of 10 years on or before this 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 | 28 Feb | 14 Oct | 228 |
| Persephone period | 15 Oct | 27 Feb | 137 |
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 | 28 Feb – 12 Apr | 44 | Grow long-day plants like spinach, lettuce and coriander. |
| Longer daylight | 14+ h | 13 Apr – 29 Aug | 139 | High risk of bolting |
| Shorter daylight | 10-14 h | 30 Aug – 14 Oct | 46 | Grow long-day plants |
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