Take time now to learn how to take care of strawberry plants in the wintertime outdoors for a bountiful crop next summer. Strawberries require winter protection, especially in areas where temperatures dip below 15 to 20 degrees Fahrenheit.
- Thinning Runners and Older Plants
- Watering Before Dormancy
- Mulching Against Weather
- Row Covers for Strawberry Plants
- Pruning the Beds
- Fertilizing Times
- Caring for Strawberries Is Easy
- Winterizing Strawberry Plants: How Do You Protect Strawberry Plants In Winter
- How Can I Overwinter Strawberry Plants?
- How To Prepare Strawberry Plants For Winter
- Yard and Garden: Prepare Strawberry Plants for Winter
Thinning Runners and Older Plants
Follow these essential tasks to give your strawberry plants the best chance of overwintering unscathed.
Space Between Plants
Strawberries grow best when there is enough space between the plants. You should strive for approximately five plants per square foot (with more space given to plants that produce vigorous and plentiful runners). Examine the strawberry beds in the fall and decide which plants you can move or remove entirely. Look for vigorous growth near the crown or center of the plant.
Removal and Transplanting
Any plants exhibiting crown rot, poor growth habits, or poor crown development should be removed. Transplant healthy plants to extend the existing strawberry bed or create new beds in the garden – or in containers. You can also give some plants away to a grateful local gardener; you’re sure to find takers for healthy strawberry plants!
Winter Display Tip
Strawberry plants, their trailing runners, white blooms, and scarlet berries are unique additions to container gardens, window boxes, and ornamental displays.
Watering Before Dormancy
Strawberries, like many fruit trees and plants, determine the quantity of fruit they will produce based on the prior year’s fall weather. Abundant fall rainfall is essential to vigorous fruit production.
If your area doesn’t receive at least one inch of rainwater per week starting in late September or early October, supplement the rain with irrigation. Gardeners in the northern part of the United States may need to begin watering earlier.
Mulching Against Weather
Consider adding straw or salt marsh hay over the beds if winter temperatures can reach below about 20 degrees Fahrenheit. Strawberries, especially the tender new growth and crowns, can sustain frost damage during prolonged cold spells or unusual cold snaps.
Regions Above Zone 7
For regions above Zone 7, winter care for strawberry plants should include mulching. Apply the covering (spread a 2-3 inch layer of mulch) after the first significant frost. Many natural mulches – such as pine needles, wood chips or straw – are the best choices. Avoid manure and hay. Manure will “burn” plants and hay will yield a flourishing crop of weeds in the spring!
Frost Is Needed Before Mulching
Be sure to wait until the ground has received a heavy frost before mulching the beds. The ground should be frozen with sustained cold daytime temperatures – at or near freezing. Covering strawberry plants too soon may result in rot. Cover the plants before deep freezes, snow or ice.
Row Covers for Strawberry Plants
Some gardeners like to use row covers to protect strawberry plants, rather than mulch. A row cover is a plastic fabric draped over a frame. Use row covers made from a clear material in order for sunlight to filter through to the plants. Be sure to place a row cover over the plants when the weather turns cold, and to remove the fabric in early spring.
Synthetic covers left on too long can cause the plants to become acclimated to the warmer microclimate underneath the cover leading to weather shock. If temperatures begin to warm prematurely, or the sun is heating the covered beds, plants can suffer from an increased possibility of burn, shock or fungal disease.
Pruning the Beds
Winterizing strawberry plants includes selective pruning. However, in order to encourage regular yields from the plants, you will need to replant the beds or cull the old berries. The pruning you do depends on the type of plants you have.
If you are growing an everbearer, dig out or mow the original plants in order to create new beds of purchased berries or to allow the rooted “runners” (new plants that grow from long, side-growing stems) to flourish.
Everbearer types produce the best fruit during the first few years. Monitor the yields to decide when the plants should be removed. Small, yellowing or weakened plants with reduced fruiting are ready for replacing.
June strawberries can set berries for several more years. Trim the plants by pruning off the old leaves, and the top levels of growth in the fall. Generally trim off the first 1/2 inch or more if the plant is overly vigorous. If you have large areas of beds (flat, not raise beds), adjust your mower to the highest setting and mow over the beds. This is done after berry production – around late August/September. Pruning encourages the strawberry to produce more fruit and it helps to mitigate disease.
Strawberries are rugged plants, but they enjoy some extra nutrition in order to stay vigorous and produce heavier crops of berries. Fertilize the plants in the spring and the fall using a general 10-10-10 fertilizer. Follow the manufacturer’s directions for application on berries. How much fertilizer you need will depend on your soil test results and the amount of other products you use (water soluble fertilizers and organic mulches/nutrients).
Organic fertilizers are widely available for gardeners. You can augment purchased supplements with compost, lime, crushed stone and other degraded manures such as cow, earthworm, chicken, horse or rabbit.
If you notice the strawberry plants are not producing well or are revealing yellowing of their leaves, it may be time to add a fertilizer product. If these symptoms are exhibited by older plants, cull the aging bed and replace the rows with new strawberries. Before planting the replacements, dig in some loam or compost to enrich the soil. Mulch the new plants with straw or marsh hay.
Caring for Strawberries Is Easy
Luckily, strawberries are actually quite hardy plants, and can survive the winter very well. By following the simple winterizing steps, your plants will emerge in the spring – ready to flower and fruit!
Winterizing Strawberry Plants: How Do You Protect Strawberry Plants In Winter
Strawberries are great plants to have in the garden. They take up little space, they’re prolific, and they’re delicious. They’re also reasonably hardy. They are not, however, quite as hardy as you might think. While it’s true that strawberries are grown extensively across Canada and the northern U.S., they can actually suffer serious cold damage if they’re not protected adequately. Keep reading to learn more about protecting strawberry plants in winter.
How Can I Overwinter Strawberry Plants?
So how do you protect strawberry plants in winter? One important step to winterizing strawberry plants is thinning them out. Strawberries spread fast, so you don’t need to worry about knocking them back too far – think of it as pruning. Thin until you have about five plants per square foot. Make sure to remove any plants that look diseased.
Another important thing to consider when winterizing strawberries is water. Strawberry plants need plenty of water in the fall to ensure their health over the winter and into the spring. If your plants are getting less than 1 to 2 inches of rain per week in the fall, supplement with water.
Maybe the best known, and most important, means of protecting strawberry plants in winter is mulching. Wait until the plants have gone dormant, or you risk smothering them. A good indicator that the plants have gone dormant is that they sort of flatten out against the ground. This should happen when the daytime temperatures are in the 40s (C.) and nighttime temperatures are in the 20s (C.).
At this time, bury your plants in 3 to 6 inches of loose straw, pine needles, or wood chips. Stay away from hay, as this is usually full of seed that will sprout and clog your plants in the spring. Make sure to remove the mulch in the spring to keep your plants from smothering.
The temperatures are starting to plummet, and that means it is time to prepare your strawberry plants for winter, whether you grow them in the ground, or in pots!
Strawberries are one of the easiest perennials to grow. But they do require a little preventive care before winter to ensure a healthy, productive crop the following year.
Strawberries require protection from winter’s heavy frosts and freezes. Without it, they can easily freeze out.
Here is a look at how to prepare your planted or potted strawberry plants to survive winter’s fury.
How To Prepare Strawberry Plants For Winter
Strawberries Planted In The Ground
Let’s first take a look at planted strawberries. First and foremost, all strawberry plants need to be protected from the cold.
For plants in the ground, that means applying a heavy 4 to 6″ thick mulch of straw, shredded leaves, or even pine needles in late fall.
When it comes to mulch, the key is choosing a material that allows for air to still get to the plants and roots below.
A 4 to 6″ mulching of plants will prepare and protect strawberries from winter’s freezing temperatures
If using leaves, shredding is a better option that whole leaves. Whole leaves can become soggy and thick, and smother plants out.
Strawberries should be mulched in late fall, once they have gone dormant for the season. Check near the crown of the plants, and if there is no new green growth, they are ready to be mulched.
Should I Prune Or Cut Back Plants Before Mulching?
This question comes up often when it comes to caring for strawberries. One thing is for sure, never mow or prune back strawberry plants in the fall!
For one, next year’s fruit already set on the plants. And cutting them back at this point eliminates next year’s fruit. But it also leaves plants with little to no protection, and most likely will result in a total loss of the plants.
Cutting back or mowing off strawberry plants should only be done right after they have finished fruiting in early summer, and never in the fall!
Cutting back or mowing off plants is an excellent idea to build vitality and strength in plants.
But it should only be performed after their last fruiting in the early summer, giving them time for regrowth before going into dormancy.
Potted Strawberry Plants
Potted strawberry plants are a bit more susceptible to the freezing temperatures of winter than those planted in the ground.
But with that said, winter care is pretty simple and straightforward as long as you bring them in out of harms way.
Potted strawberries need a bit of extra protection to survive winter.
Unless you live in an arid climate with warm winter temperatures, potted strawberries need protection from freezing out.
How To Protect Potted Strawberry Plants
An unheated garage, barn, or shed are all great options for giving potted strawberries protection.
Bringing them out of the direct cold is a great start, but providing a little extra cover is a good idea. This can be done easily with a few different methods.
Placing pots inside a burlap sack, or wrapping them in burlap and then filling with straw will usually do the trick.
Burlap is an excellent material to use for wrapping potted strawberry plants.
The burlap and straw provide protection, while still allowing the plants to breathe.
Another option is to place pots in a 5 gallon bucket and surround with straw or shredded leaves. If none of these options are available, you can also bury the pots in the soil outside, and cover with 6 inches of straw.
Once spring arrives, all potted plants can then be uncovered and brought back outdoors.
Be sure to not allow the soil in potted plants to completely dry out over winter. The plants still require moisture to survive, even in their dormant state.
Check soil every week or so and water as needed.
For more on growing strawberries, see our article, How To Plant And Grow Strawberries.
This Is My Garden
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I planted a strawberry patch this fall and have heard that I should cover the plants with mulch for the winter. Is this true? If so, what should I use for mulch?
Yes, I would recommend mulching your strawberry bed for several reasons. The most important being that a good layer of mulch will prevent the plants from heaving out of the ground in winter as temperatures fluctuate, causing the soil to alternately freeze and thaw. Heaving is more likely to occur in a heavy soil than in a sandy one, but no matter what type of soil you have, there are additional benefits of mulching such as conserving moisture and reducing weeds the following spring.
Wait to mulch your beds until after the first hard freeze, when the soil is frozen to about 1/2 an inch below the surface. Do not apply mulch during warm weather because this may cause the plants to begin growing and when the temperatures turn cold again they will be damaged.
The process I follow is to first cover the plants with a loose arrangement of small branches. This will prevent the mulch from smothering the plants. Then scatter your mulch material on top. I prefer to use wheat straw because it is less likely to pack down, but pine needles or even shredded newspaper will work as well. If you use newspaper, discard the slick pullouts and magazines because their inks contain heavy metals. Avoid using tree leaves, bark mulch or saw dust because they mat when wet.
Once the mulch material is applied, add another layer of twigs and branches to keep it in place and then lightly hose down the area with water.
Remove the mulch in spring after the last frost date in your area. Rather than discard the mulch, simply transfer it to the area between your plants to help retain moisture, prevent weeds and to keep the berries off the ground.
Posted by Christina Herrick|November 12, 2009
Submitted by: Rich Marini, Department of Horticulture, Penn State University
Mulching strawberries is an old practice that helps protect the plants from low temperature injury during the winter and keeps the ripening fruit clean. This summer Kathy Demchak and I observed winter injury in the crowns of plants in strawberry fields that were not mulched until mid-winter. Although few plants were killed, the injury appeared severe enough in some plants that yield was probably reduced. For strawberries grown on raised beds, the potential for cold injury is high because soil heat may quickly dissipate from the increased surface area of the beds relative to the soil volume. Covering raised beds with plastic or row covers likely retards heat loss, but I am not aware of soil temperature data for raised beds with different types of covers. This article is intended as a review of the information on mulching strawberries and on low temperature injury, so growers understand how and when to effectively mulch their plantings.
In the late summer and early fall, strawberry plants enter a physiological stage referred as “dormancy.” There are different phases of dormancy, but that discussion is beyond the scope of this article. Although dormant plants do not appear to be growing, the buds continue to develop throughout the winter. The initial stages of dormancy are triggered by decreasing day length and declining temperatures, but strawberry plants do not become hardy until November. The term “hardiness” refers to the plant’s ability to resist low temperatures. As strawberry plants become dormant, new leaf development ceases, the leaf petioles become more horizontal, resulting in the “flattened” appearance of dormant plants, and older leaves turn red. Plants become hardy upon exposure to freezing temperatures, and strawberry plants continue to increase in hardiness until January. In late winter, after being exposed to sufficient chilling, the plants start to lose cold hardiness in response to warming temperatures. Upon exposure to sufficient heat, the plants begin to grow.
Mulch should be applied after the plants have attained substantial cold hardiness, but before low temperatures injure the plants. A rule of thumb, supported by research data from several locations, is to apply mulch after three consecutive days when the soil temperature is 40°F or lower at a 4-inch depth. This usually occurs after several hard frosts in the low 20s, and in Pennsylvania this usually occurs between mid-November and mid-December, depending on location.
Strawberry plants are covered with straw to insulate plants from low temperatures, to prevent temperature fluctuations that can lead to frost heaving, and to minimize plant desiccation. Mulch also delays soil warming in the spring and minimizes exposure to spring frost by delaying bloom. Following bloom, mulch helps with weed control, conserves soil moisture, and helps keep fruit clean. Several types of loose materials have been successfully used as mulch, but straw is most common in the northeastern U.S. Hay should be avoided because it contains weed seeds. For matted rows, about 2.5 to 3 tons of mulch per acre, providing a 2- or 3-inch-layer, is typically applied on top of the plants. Doubling this amount of mulch is typically suggested for raised beds. Snow is an excellent insulator, and snow combined with mulch is even better. My Master’s research at the University of Vermont involved laboratory experiments where plants were exposed to various temperatures to determine critical temperatures for plant growth, as well as survival of plants and flower buds. In a field experiment, non-mulched strawberry plants were compared with mulched plants. When the air temperature was -4°F, the temperature of non-mulched crowns was 1.5°F, but the temperature of crowns under straw mulch plus 8 inches of snow was 30°F.
Mulch is typically removed in early spring when plants begin to show signs of growth or new leaf emergence under the mulch. Earlier mulch removal will allow the soil to warm, resulting in earlier plant growth and bloom, which is susceptible to spring frost. The mulch should be removed with rakes or pitchforks in small plantings or with various types of mechanical rakes in larger plantings. A little mulch should remain on the plants, and this will work its way to the soil surface to help keep fruit dry and clean, but most of the mulch is pulled to the row middles for weed control.
Christina Herrick is the Senior Editor of American Fruit Grower magazine and Western Fruit Grower magazine, published by Meister Media Worldwide. See all author stories here.
Yard and Garden: Prepare Strawberry Plants for Winter
As temperatures move closer to freezing and below, remember the sweet, delicious June strawberries from your garden and take time to protect the plants – and next season’s crop. Just like many people, strawberry plants don’t like to feel those colder temperatures. Iowa State University Extension horticulturists tell how to protect plants through the winter. Gardeners with additional questions should contact the ISU Extension Hortline at [email protected] or call 515-294-3108.
When should I mulch my strawberry bed?
Cold winter temperatures and repeated freezing and thawing of the soil through the winter months are the main threats to strawberry plants. Temperatures below +20 F may kill flower buds and damage the roots and crowns of unmulched plants. Plants also can be destroyed by repeated freezing and thawing of the soil, which can heave unmulched plants out of the ground.
Strawberries should be mulched in fall before temperatures drop below +20 F. However, allow the strawberry plants to harden or acclimate to cool fall temperatures before mulching the planting. Plants that are mulched prematurely are more susceptible to winter injury than those that are mulched after they have been properly hardened. In northern Iowa, strawberries are normally mulched in late October to early November. Gardeners in central and southern Iowa should mulch their strawberry plantings in mid-November and mid- to late November, respectively.
What materials are suitable for mulching strawberries?
Excellent mulching materials include clean, weed-free oat, wheat or soybean straw. Chopped cornstalks are another possibility. The depth of the mulch should be 3 to 5 inches at application. The material should eventually settle to 2 to 4 inches.
In windy, exposed areas, straw mulches can be kept in place by placing wire or plastic fencing over the area. The fencing can be held in place with bricks or other heavy objects.
Are leaves a suitable mulch for strawberries?
Leaves are not a good winter mulch for strawberries. Leaves can mat together in layers, trapping air and creating space for ice to form. The leaf, air and ice layers do not provide adequate protection. Leaf mulch actually may damage plants due to excess moisture trapped under the material.
How do I protect strawberry plants growing in a strawberry pyramid?
A strawberry pyramid is a type of raised bed. In winter, temperatures in raised beds may be several degrees colder than ground level plantings. Because of colder temperatures, strawberry plants growing in raised beds require more protection that ground level sites. Place 6 to 8 inches of straw or chopped cornstalks on strawberry pyramids or other raised beds in fall.
How do I protect strawberry plants growing in a strawberry jar?
Strawberry plants growing in a strawberry jar or other container likely will be seriously damaged or destroyed if left outdoors in winter. One option is to place the container in an attached, unheated garage in November. A second option would be to discard the strawberry plants in fall, dump out the potting soil, store the container indoors in winter and replant in spring. Day-neutral and everbearing strawberry varieties perform better in containers than June-bearing strawberries.