Length of vegetation period

Flicka känner på bladen av en buske.

The period during the year when there is sufficient warmth and moisture for plants to grow is commonly referred to as the vegetation period. This factor has become increasingly important for seeing how the climate is changing.

The vegetation period is usually defined as the part of the year when the average daytime temperature is above a particular threshold. This threshold depends on the type of plant, but is usually between +3°C and +5°C.

In northern Sweden, the length of the vegetation period has increased by around two weeks over the last 40 years. The length of the vegetation period has also increased in southern Sweden, but not by as much. In southern Sweden, this increase has also mainly been concentrated on the last decade.

Climate scenarios suggest that the vegetation period will become longer in future throughout the country.

A longer vegetation period may lead to certain agricultural harvests increasing in future, and may provide opportunities to grow new crops. It may also benefit forest growth. This is provided that the crops or forests have sufficient water at their disposition.

At the same time, the risk of pests and harmful fungi will also increase.