Winterizing Strawberry Plants
Julie Martens Forney
Protecting strawberry plants from winter’s cold temperatures is vital to ensure a crop of juicy berries next year. Winterizing strawberry plants isn’t difficult or expensive. It’s actually an easy chore on your garden to-do list. Learn tips for winterizing strawberry plants.
By the time fall frosts arrive, strawberry plants have already set buds for next spring’s flowers. Temperatures below 15° F can damage those new buds and diminish your berry crop next year. This is why it’s vital to winterize strawberry plants and protect them from cold winter air.
Another reason to protect plants is that, when soil repeatedly freezes and thaws, it tends to push plants up. This process is called heaving and puts plants at risk in several ways. First, it can expose plant crowns to drying air, freezing air temperatures and hungry critters looking for a winter meal. Second, heaving can break roots, allowing them to be lifted completely out of soil. Either results in plant damage or death. Winterizing strawberry plants helps prevent heaving.
Winterizing strawberry plants simply involves heaping mulch over plants so they’re not exposed to cold winter air. The trick is knowing when to apply the mulch. You want to cover plants when they’re fully dormant. Cover too soon, and plants may fail to harden off, which means they’ll definitely be damaged by cold air. A too-soon mulch also risks rotting plant crowns.
It’s safe to apply winterizing mulch to strawberry plants when the top one-half inch of soil has frozen and daytime temperatures stay consistently in the 20s. In mild winter areas, apply mulch once soil temperatures hit 40° F for three days in a row. Definitely winterize strawberry plants before temperatures dip below 20° F. Precise timing varies depending on region. Fine-tune the timing with a call to your local extension office.
To winterize strawberry plants, heap a loose mulch over plants to a depth of 3 to 5 inches. Use a material that won’t compact heavily. Good choices include straw, clean hay, bark chips, chopped cornstalks or cobs, evergreen branches or pine straw. Materials like leaves or grass clippings aren’t a good choice because they tend to mat. After mulch settles, it should still provide a 2- to 3-inch depth for best protection.
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Using a frost blanket to winterize strawberry plants is another great choice because it allows light to reach plants, which results in more flower buds being formed. The tricky part is that plants experience faster flower development in spring, which means they’ll be at greater risk for cold damage if you fail to protect plants when a late-season frost is predicted.
To winterize strawberry plants in a pyramid, apply mulch 6 to 8 inches deep. Wrap large strawberry pots or barrels with burlap and/or bubble wrap and stuff the top opening with straw 6 to 8 inches deep. Move strawberry jars into an unheated garage for winter.
Remove winterizing mulch in spring as growth resumes. Consider raking it into rows and around plants to serve as a growing season mulch. Keep it nearby in case you have to heap it over plants again in the event of a late spring frost.
