How to Winterize Strawberry Beds
When to cover strawberries with straw, how deep to spread it, and when to pull it off in spring. Timing from University of Minnesota and West Virginia Uni...
Published by ThriveThyme
strawberries fruit winter mulch
Some outbound seed-house links may be affiliate links.
How to Winterize Strawberry Beds
Strawberry crowns sit right at the soil surface, and next year's flower buds form in fall. West Virginia University Extension notes that temperatures below 20F can kill flower buds and injure the crowns of unmulched plants, and freeze-thaw cycles can heave plants out of the ground. A straw blanket, put on at the right time, prevents both.
When to Mulch
Wait until plants are dormant. Straw on plants that are still growing weakens them.
- Soil rule: University of Minnesota Extension recommends mulching once soil at 4 inches has stayed at or below 40F for 3 days in a row.
- Frost rule: UMN's home garden advice is to cover plants after 2 or 3 frosts have hardened them off.
- Plant signs: WVU notes dormant plants flatten out and the leaves turn light red or green.
- Board test: UMN suggests laying plywood over a few plants for 3 days. If the leaves underneath stay green, plants are dormant. If they turn yellow, wait.
Typical timing is November in Minnesota and around Thanksgiving in West Virginia. If a sudden drop below 20F is forecast, WVU advises mulching right away even if plants are not fully hardened.
How Much Straw
- Use clean, weed-free wheat or rye straw. Hay carries weed seed.
- Spread 4 to 6 inches of loose straw over the plants, the depth UMN and WVU give for home beds. UMN's guidance for farms is to cover plants 2 to 3 inches deep.
- Shake bales apart so there are no dense clumps.
- Snow on top of the straw adds insulation. Do not rush to mulch just because an early snow fell.
Zone Notes
- Zones 3 to 7: Straw mulch is standard. Without it, crowns and buds are exposed whenever there is no snow cover. UMN says Minnesota winters are too cold for strawberries to thrive year to year without it.
- Zones 8 to 10: Crowns rarely need a thick blanket, but buds can still be hurt below about 20F. Keep a light straw mulch and cover plants when a hard freeze is forecast.
- Containers: UMN suggests moving pots to a spot that stays between 20F and 40F all winter. Most garages get colder than that, so the other option is to set pots on the ground and insulate them with mulch or soil.
Removing Straw in Spring
- Pull straw off when soil reaches about 40F and the first new leaves start to grow. In Minnesota that is mid-April to early May.
- Rake it into the aisles and leave some around the plants as summer mulch. It keeps berries off the soil.
- Leaving straw on too long delays harvest and lowers yield. Pulling it too early raises frost risk.
Everbearing and Day-Neutral Plants
Home beds of everbearing plants are mulched the same way. UMN's farm guidance does not recommend overwintering day-neutral plantings.
Next Steps
Read June-bearing strawberries first year by zone, check the zone line on the strawberry plant page, and tick the strawberry task on Garden to Bed. For a new bed next spring, Seeds Now sells strawberry plants and roots.
Sources
- University of Minnesota Extension, Growing strawberries in the home garden
- University of Minnesota Extension, Adding and removing straw mulch for strawberries
- University of Minnesota Extension, Cover strawberries with straw for the winter
- West Virginia University Extension, Getting Strawberry Plants Ready for Winter