Don't Get in a Rush to Apply Mulch to Your Strawberry Bed This Fall

November is often the time we think about applying mulch to strawberry beds in Iowa.  The purpose of mulching in strawberries is to buffer the temperatures that the plant crowns will experience in the winter and reduce the desiccation of the plants that can happen with our cold, dry winter winds.   

While annual applications of mulch in the fall is a good practice, it's also something we don't want to do too early, since covering up the plants before they are fully dormant can have negative effects on their health.  Some general guidelines are that strawberries in the northern part of the state are often mulched in early November and mid to late November in the southern parts.  Given the mild temperatures we have seen so far this fall, look for several indicators that suggest it is time to apply mulch, rather than basing that decision on a calendar date.  There is a good chance it may be later than normal this year. 

Factors to Consider When Applying Mulch to Strawberries

• Indicators that the plants are dormant
  • Cover: you can cover a small section of your strawberry bed with board or mulch for several days.  If the leaves have not etiolated (turned a yellow color) due to a lack of light, they are approaching dormancy. 
  • Color: leaves on dormant strawberry plants will not have the vibrant green they have during the growing season (Figure 1), but instead will have a grayish or sometimes reddish cast to them that indicates that they are dormant.
• Several consecutive nights of around 20F. 
• Soil temperatures consistently below 40F for several consecutive days.
  • Most of us don’t have a soil thermometer, but there is data for each county on the Iowa Environmental Mesonet webpage.