IRRIGATION METHOD AND ROWCOVER USE FOR STRAWBERRY FREEZE PROTECTION

Three irrigation treatments (none, drip, and sprinkler) and eight rowcover treatments were evaluated for their capacity to provide freeze protection for strawberries (Fragaria xananassa Duch.) in a split-plot factorial field experiment. The period under study included 20 freeze events, two events with minima of -9.5C and -10.0C. With no freeze protection, up to 93% of the flowers were damaged by freezes. Among sprinkler-irrigated plants, an average of only 10% flowers were damaged due to the freezes. Heavy-weight rowcovers (polyethylene blanket and polypropylene, 30 and 50 g.m-2, respectively) protected strawberry flowers as well as sprinkler irrigation to -4.4C. Early yield (December-January) from unprotected plants was negligible. Early yields from plants protected with a 3.2-mm polyethylene blanket or a 50 g.m-2 polypropylene cover were equal to yields obtained with sprinkler-protected plants. Combinations of sprinkler and certain rowcover treatments provided for better fruit production than either treatment alone. Drip irrigation alone provided no protection from freezes. All strawberry plants recovered from freeze damage and total-season yields were similar with all irrigation methods and rowcovers.