OVERWINTER ROWCOVERS INCREASE YIELD AND EARLINESS IN STRAWBERRY
Strawberry plants planted in May of each year, 1983–85 and 1987, were overwintered under different rowcovers to determine their effect on production of marketable fruit, earliness to bloom and harvest, degree day accumulation and susceptibility of flower buds to spring frost. Rowcover treatments of spunbonded polypropylene, polyester or polyamide, or of slitted polyethylene film, and a no rowcover treatment were applied in early autumn 1983–85 and were removed at first bloom in spring. A straw mulch was applied in early winter to half of the plots in each treatment. Mulch was removed in spring when new growth emerged. Treatments were rowcover, rowcover + mulch, no rowcover and no rowcover + mulch. Rowcover treatmetns increased marketable production in each year. Plants bloomed as much as 13 days earlier and matured as much as 10 days earlier in rowcover treatments compared to other treatments. In 1987 a rowcover treatment of extruded polypropylene-polyamide mesh and a no rowcover treatment were applied in autumn followed by straw mulch applied to each in early winter. The rowcover treatment increased degree day accumulatin in autumn and spring compared to no rowcover. Rowcovers increased numbers of primary, secondary and tertiary flowers. Frost damage was greater for primary and secondary flowers under rowcovers. Conclusions are that rowcovers increase marketable fruit by increasing numbers of flowers, that the primary effects of rowcovers on production and earliness to maturity occur in spring and that rowcovers may not provide adequate protection from frost to emerging flower buds.
Pollard, J.E., Gast, K.L.B. and Cundari, C.M. (1989). OVERWINTER ROWCOVERS INCREASE YIELD AND EARLINESS IN STRAWBERRY. Acta Hortic. 265, 229-234