By Bernard Zandstra
Action now will improve the strawberry crop next year.
Perennial strawberries (matted row production) are normally planted on bare ground in the spring, maintained the first year with herbicides, fertilizer and irrigation, and then harvested for two to three years. After the first year harvest (normally a two- to three-week period), the strawberries need to be renovated, which means clearing out the weeds, removing the old foliage and preparing the field for another year of growth. The renovation process allows the roots to send up new shoots, which then send out runners and fill the “matted row.”
After the last harvest of the season, the strawberry plants should be mowed to destroy old foliage that may be infected with foliar diseases. The roots should not be disturbed. After mowing, apply 2,4-D (Formula 40) plus a post-emergence grass herbicide to kill the weeds present. Apply a complete fertilizer according to a soil test. Wait a week and then narrow the rows to 10 inches with a rotary tiller. Apply post-renovation herbicides.
Several residual herbicides may be used at renovation. Sinbar, Spartan, Prowl H2O and Ultra Blazer are labeled for application at renovation. Sinbar should not be used on light sandy soil with less than 1 percent organic matter. Combinations of Sinbar, Spartan or Ultra Blazer with Prowl H2O provide a broad spectrum of weed control. None of these combinations will provide adequate control of perennial weeds.
After the new shoots have been established and the strawberry plants are regrowing, Stinger may be applied to kill emerged composites, legumes, nightshade, smartweeds and plantains. Some weeds that are difficult to control are wild geranium, field pansy, white campion, mayweed and horseweed. Stinger will control the composites, but others may have to be removed by hand. Another application of the grass herbicides Poast or Select Max will help control annual and perennial grasses. Quackgrass must be controlled in strawberry.
Good weed control after harvest and for the rest of the growing season is important for maximum strawberry fruit production the next year. The field should be irrigated regularly to maintain good plant growth. By the end of the summer, the plants should be about 10 inches tall with full rows of bright green plants. Poor growth later in the season results in reduced yields the following year.