Predicting Strawberry Progress with Heat Units

Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu

Frost protection and row cover management has been simple so far this winter on Delmarva – Keep the covers on.

As spring progresses, you will need to decide when to remove covers, and once covers are removed, when to start frost protection.

Work in North Carolina has shown that strawberries achieve first bloom when they have accumulated 90 Degree Days (base 50, the same we use for corn). This refers to the Camarosa variety and may be slightly different for other varieties such as Sweet Charlie and Chandler.

On Delmarva, growers can look at degree days and once it gets over 80, start looking for bloom in their crops.

In Delaware, degree day calculations can be found on the DEOS weather site in the Ag/Irrigation summaries section http://www.deos.udel.edu/agirrigation_retrieval.html. Choose the closest site to your farm and look for the GDD column. Start in February and add up the GDD units. So far, for most of the state, we have had less than 5 GDD.