Strawberries Not Overwintering - Solution Guide
Strawberry plants are tougher and hardier than many gardeners give them credit for. However, several different factors can lead to strawberry plants not overwintering successfully. Following these important steps for winterizing strawberries can prevent major disasters such as losing entire crops. Below are some of the most common reasons overwintering fails, and we offer valuable solutions to avoid the disappointment of finding dead strawberry plants come springtime.
Covering too early
If plants are not allowed to go naturally dormant from a few hard frosts (28°-29°F) and are covered too soon, they can continue to grow even though they are covered. Then, when temperatures eventually get cold, this kills them off.
Solution: Wait until plants are dormant to cover for winter. The best time to cover your strawberries in cold climates is around Thanksgiving. The ground should be very cold, if not frozen.
Covering them too shallowly
Covering strawberries should happen after they have gone dormant from several hard freezes. If the mulch is too shallow, crowns are left too exposed and can freeze to death.
Solution: Proper cover of at least 4 inches of settled straw is necessary in cold weather climates to keep crowns safe. This means about 6-8 inches of straw cover is needed initially. Winter winds can often blow enough to deplete straw depth. Take care to check the status during winter and reapply straw as needed.
Thawing & Re-freezing
The proper depth of straw cover helps prevent potential thawing and re-freezing damage, which is also common in winter.
Solution: Proper covering material can be clean straw, pine needles, or marsh hay. Some clean tree leaves can be used if those leaves are shredded first. Whole leaves mat and hold too much moisture. (Maple tree leaves should be avoided because they often harbor fungal pathogens.)
Soil is kept too dry
Strawberries are shallow-rooted, and soil allowed to dry too much will lead to the desiccation of roots, foliage, and crowns.
Solution: Maintain consistent soil moisture going into fall. If conditions are dry, water. Contrary to most gardeners' beliefs, water does not encourage growth, but proper moisture will keep roots hydrated in winter. Desiccation is a common winter killer of strawberries due to the porous soils they prefer. Be sure you water the strawberries until you cover them for the winter.
Soil kept too wet
Yes, this is a double-edged sword of strawberry care. If the soil becomes too saturated, dormant strawberry plants with inactive growth can quickly rot from too much moisture. Especially newly planted crops.
Solution: Ensure the soil is appropriately amended to provide proper drainage at planting. Plants can rot during cold winters while undercover if the soil is too heavy.
Renovating too late
If renovation (cutting back) of mature crops is done too late in the season, strawberries may not have enough time to regrow before dormancy, which causes stress, and plants can fail to overwinter correctly.
Solution: In most climates' plants should be renovated around the end of July or the first week of August to allow plants enough time to recover. An even better time to renovate them is after the strawberries stop fruiting. Mow the plants off with your mower set as high as possible. Then, renovate and fertilize the plants so they can re-establish before winter.
Importantly
Strawberry plants that perish over the winter most likely succumbed to a combination of adverse cultural or environmental conditions. Rarely is one single issue to blame. To prevent overwintering problems, all strawberry growers should review and consider all these troubleshooting factors and solutions to ensure that all proper cultural guidelines are followed.
The other truth is that healthy growing crops that are adequately protected for winter will be a success. On the other hand, if strawberry plants do not survive the winter, some adverse or unfavorable conditions cause their demise, and it behooves the gardener to research which specific issues have occurred to avoid similar problems in the future.
View the Garden Doctor video on YouTube for further information on overwintering strawberries.
