Normally, strawberries should be mulched for the winter around Thanksgiving. However, if temperatures stay abnormally warm, give plants another couple of weeks to become cold hardy before mulching. Mulching plants helps protect strawberries not only from low temperatures but also from heaving damage. Heaving damage occurs when the alternate freezing and thawing common in Kansas winters heave plants out of the ground where the roots are exposed and the plants die from lack of water.
Wheat straw makes good mulch and is widely available. The straw should be spread over the plants to a depth of 3 inches. Shake the slabs of straw apart so there are no large compressed chunks. This straw mulch not only helps protect the plants over winter but can also help avoid damage from late spring frosts by delaying blooming a few days in the spring. Mulch should be removed gradually in the spring as plants begin new growth. Remove enough so leaves can be seen.
Leaving some mulch in place keeps the berries off the ground and conserves moisture. Also, mulch left in the aisles helps protect pickers from muddy conditions. (Ward Upham)