Strawberry cold injury: Factors increasing risk of damage

Read about the nine factors that increased the risk of freezing damage in strawberry. These were observed following the winter of 2010/2011.

1. Soft growth

Soft growth in late autumn preceding a severe cold spell. A reduction in nitrogen use during October will prevent an abundance of lush growth.

2. Older crowns

Older crowns (i.e. over two seasons old) were more severely damaged than well-grown one-year-old crowns in 2010/11. Older crowns are more elongated and exposed to wind chill.

3. Shallow planted crowns

Shallow planted crowns with much of the crown proud of the compost – commonly found in tray plants.

4. Crops on tabletops

Bags and troughs in the air fared worse than those on or near the ground in 2010/11.

They are more exposed to wind run that cools the crowns more quickly.

Ground-based crops can also benefit from a prolonged snow covering, though the presence of snow cannot be guaranteed every time there is a cold spell.

5. Frost pockets and windy areas

Location in known frost pockets and windy areas.

In 2010/11, it was common to see highly variable damage across a single field with uneven topography.

6. Waterlogging

In a few cases in 2010/11, there was poor drainage in ground-based bags.

• Poorly-drained composts contain more water.
• Moisture protects against cold damage up to a point as it releases heat as the ground begins to freeze.

However, once frozen it is highly damaging as large quantities of ice prolong cold exposure to roots, which may already be weakened by root diseases that thrive in cold, wet conditions.

7. Crown desiccation

Crown desiccation occurs in windy conditions, drawing water from the leaf canopy, but this cannot be replaced by the roots as they are frozen.

8. Soil with long grass

Soil with long grass will hold less heat for release at night than if the grass is mown short.

9. Variety

Sonata generally seemed to survive better than Elsanta in 2010/11, but there are many other variables which may confuse this comparison.

The HDC main season strawberry variety trial showed no winter damage across nineteen varieties in 2011.

It was planted in 2010 as a 60-day soil crop, based in Staffordshire and was buried in snow.

No trial data exists which allows comparisons to be made between the significance of these factors.

However, it is certain that protective measures will help to reduce the speed of chilling, thus increasing the lowest crop temperature and the duration of such a temperature.

Original author

Robert Irving, ADAS