Because I love strawberries and garden a lot, I was excited to start growing my own patch of juicy, sweet strawberries. But I quickly learned that it took more care and planning than I thought to keep strawberries alive through the cold winters. I’ve learned the right way to winterize strawberry plants so that they produce lots of fruit every year through trial and error and a lot of research.
I will tell you everything I know about when and how to cover strawberries for the winter in this full guide. Whether you’ve grown strawberries before or this is your first time, this guide will help your plants make it through the winter and do well come spring. Let’s get growing!.
Why Winter Protection is Crucial for Strawberries
Strawberries are perennials in growing Zones 4 and up, meaning the plants can technically survive winters and regrow every spring. However, extremely cold temperatures can damage or kill uncovered strawberry plants That’s because as the soil freezes and thaws repeatedly, strawberry crowns get pushed out of the ground and delicate roots get damaged
Temperatures below 15°F are especially bad for strawberry plants and often kill them if they are not protected. Even if plants survive, their fruit production suffers. Strawberries make fruit buds for the next year in the summer and fall. When the temperature drops in the winter, those buds get hurt, which means there won’t be much of a harvest the next year.
That’s why proper winter care is so important for healthy productive strawberry plants. The steps for winterizing strawberries help insulate plants from extreme cold and prevent freeze/thaw cycles from taking a toll on their root systems.
When to Winterize Strawberries
Proper timing is crucial when winterizing strawberries. Three signs that it’s time to winterize plants:
-
Soil temperatures drop below 40°F – Most experts recommend adding winter protection once soil temps are consistently in the 30s.
-
Daytime highs stay below freezing for multiple days – Wait for several consecutive days of sub-freezing temperatures before mulching.
-
Strawberry leaves turn brown and floppy – The “plywood test” involves covering a section of strawberries with plywood for a few days. If the covered leaves turn yellow, the plants are still actively growing. Brown, limp leaves signal dormancy.
Ideally, strawberries should be winterized in November or December, after a few light frosts but before extremely cold temperatures settle in. Mulching too early causes rot and stops plants from hardening off properly. Waiting too long leaves plants susceptible to winter damage.
How to Winterize Strawberry Plants
To ensure your strawberries overwinter successfully, follow this 3-step winterizing process:
1. Renovate Plants After Fruiting
Once your last strawberries have been picked in midsummer, it’s time to renovate your strawberry patch. This involves:
- Pruning away dead leaves, runners, and damaged growth
- Thinning plants to 4-6 inches apart
- Cutting back plants to 1-2 inches above crowns
Renovating prevents overcrowding and removes disease/pest-ridden foliage. Day-neutrals and everbearers should have dead leaves removed but don’t need cut back.
2. Fertilize Plants
About 1 month before your first fall frost, fertilize renovated strawberry plants with a balanced, granular fertilizer. This nourishes plants going into dormancy. Apply 1 pound of fertilizer per 25 plants.
3. Apply Winter Mulch
Once plants start going dormant, protect them with mulch. Use salt marsh hay, straw, pine needles, or other lightweight, organic mulch. Mound 3-5 inches over plants, covering all leaves. Replace mulch that gets blown away over winter. Shelter pots by surrounding with packing material and mulch.
When to Remove Winter Protection
Let winter mulch and covers sit until new growth emerges in spring. Then pull it away gradually to allow plants to adjust to the sunlight. Keep some mulch handy to cover plants if late spring frosts occur.
The Takeaway
Even cold-hardy strawberry varieties need protection to survive and fruit well through harsh winters. Follow these best practices for winterizing strawberries at the ideal time in fall. And don’t forget to monitor soil temperature so you mulch at just the right moment! With proper winter care, your strawberry patch will thrive for many seasons to come.
Winterizing Your Strawberry Plants – The Definitive Guide
FAQ
At what temperature should I cover my strawberry plants?
-
Open Flowers:Strawberry blossoms are most sensitive to frost damage, especially when they are fully open. Temperatures below 30°F ( -1°C) can cause significant damage.
-
Popcorn Stage Flowers:Flowers that are still in the “popcorn” stage, meaning they are starting to open but not fully developed, can tolerate slightly colder temperatures, around 26°F ( -3°C).
-
Tight Buds:Tight buds are the most frost-hardy stage and can tolerate temperatures as low as 22°F ( -6°C).
-
Winter Protection:As the season progresses and temperatures are consistently below freezing, mulching with straw or leaves is crucial to protect the plants from extreme cold and heaving damage, especially if temperatures are predicted to dip below 20°F ( -7°C).
-
Frost Protection Methods:
- Sprinklers: Sprinkling the plants with water can help to protect them from frost. The water can release latent heat as it freezes, which can help to prevent the plant tissues from freezing.
- Row Covers: Covering the plants with row covers can create a layer of insulation, which can help to raise the temperature around the plants by a few degrees.
- Mulching: Applying a thick layer of mulch (straw, leaves, etc.) around the plants can help to insulate the roots and crowns from the cold.
- Sprinklers: Sprinkling the plants with water can help to protect them from frost. The water can release latent heat as it freezes, which can help to prevent the plant tissues from freezing.
-
Temperature thresholds for frost protection:
- Above Freezing: Use sprinklers or row covers alone.
- Mid to High 20s: Use sprinklers or row covers alone.
- Low 20s or Below: Use both sprinklers and row covers.
- Above Freezing: Use sprinklers or row covers alone.
Do you completely cover strawberries for winter?
As temperatures continue to fall, and as heavier frosts are expected, strawberry plants should be covered. Mulch is one option, and she says to use one that doesn’t have any pesticide residue, doesn’t have any weeds, and has big pieces in it.
When should I winterize my strawberry plants?
In most areas, the best time to mulch or winterize strawberries is in November or early December, when daytime temperatures are consistently in the 20s, and the top 1 inch of soil is frozen. In areas with mild climates, you may want to add mulch around strawberries when the temperature drops into the 40s.
When should I cover my strawberries with straw?
The Commercial Strawberry Production on the Prairies guide says that straw is usually put down in late fall, after a few frosts but before the air temperature drops to -6. 7°C. This usually occurs between late October and Early November.