IRRIGATION METHOD AND ROWCOVER USE FOR STRAWBERRY FREEZE PROTECTION

Three irrigation treatments (none, drip, and sprinkler) and eight rowc over treatments were evaluated for their capacity to provide freeze pr otection for strawberries (Fragaria xananassa Duch.) in a split-plot f actorial field experiment. The period under study included 20 freeze e vents, two events with minima of -9.5C and -10.0C. With no freeze prot ection, up to 93% of the flowers were damaged by freezes. Among sprink ler-irrigated plants, an average of only 10% flowers were damaged due to the freezes. Heavy-weight rowcovers (polyethylene blanket and polyp ropylene, 30 and 50 g.m-2, respectively) protected strawberry flowers as well as sprinkler irrigation to -4.4C. Early yield (December-Januar y) from unprotected plants was negligible. Early yields from plants pr otected 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 recov ered from freeze damage and total-season yields were similar with all irrigation methods and rowcovers.