Strawberry plantings must be mulched for winter protection to produce consistently in Nebraska. Mulching reduces winter damage to the strawberry crown and flower buds.
Most unprotected strawberry cultivars are injured at 15 to 20 degrees, reducing flower production next year. Improved fruit quality, plant vigor, soil moisture conservation and weed control are all benefits from mulching that continues through next summer.
Protection for in-ground strawberry beds
To prevent damage, mulch plantings when fall temperatures begin to drop into the 20s, which usually happens around mid-November. Plants should be fully dormant before the mulch is applied; plant leaves will change from bright green to dull green or gray on dormant plants.
Apply a loose mulch layer, approximately four inches deep. Suitable mulches include wood chips, pine straw, evergreen boughs, straw, clean hay, chopped corn stalks or any loose mulch that will not compact heavily.
The mulch should remain on the strawberry plants until new growth begins next year, about mid-April. Blooming can be delayed by allowing the mulch layer to stay on the plants, thus reducing flower damage from late frosts, but waiting too long for removal will reduce yield.
Row covers are an effective alternative to mulch. Unlike straw mulches, light penetrates the row cover material, increasing the number of blossoms formed by the strawberry plants and, consequently, the overall yield. One disadvantage to floating row covers is that they accelerate flower development. Be prepared to protect blossoms from late frost.
As early spring flowers begin to bloom, remove the row covers or mulch to allow for pollination, but re-cover the plants at night when frost is predicted. Be sure to remove only enough mulch to expose the leaves. Place this excess mulch in the walkways between the plant rows. Partial removal of the mulch allows for plant development but delays blooming by keeping the soil cooler and slowing plant growth.
Protection for container plantings
Because plants growing in a pyramid, barrel or strawberry pot are elevated above ground level, and therefore are highly exposed to cold winter temperatures, additional winter damage can occur on roots, crowns and fruit buds. Extra care is necessary for above-ground plantings to provide adequate winter protection.
Pyramids should be mulched with 6 to 8 inches of straw after the soil is frozen.
Ideally, strawberry barrels should be moved to an unheated garage for the winter. If the barrel cannot be moved, protect plants by wrapping the barrel in burlap and stuffing it full of straw. However, even with careful mulching, some plant injury can be expected during severe winters.
Strawberry pots should be moved to an unheated garage for the winter.
Providing adequate winter protection for your strawberry planting is an important step that will aid in better fruit production next year.