Mulching Strawberry Beds for the Winter

Mulched strawberry bed

The very last gardening job performed before I can go into my version of winter hibernation is mulching the strawberry bed.  Even though strawberry plants are rated as winter hardy to zone 3, they need some additional protection to bear fruit consistently in any climate where temperatures drop below 20 degrees.

Strawberry flower buds, which produce next year's crop, begin to form in late summer.  If they are left exposed over the winter, the cold temperatures damage the flower buds, leading to poor or no fruit production the following summer.  The crowns of strawberry plants are also susceptible to frost damage if left exposed, which can ultimately kill the plant.   And, finally, with the many freeze and thaw cycles in our winters, mulch protects the plants from actually being "heaved" out of the ground with the expansion and contraction of the soil during freeze and thaw cycles.

Knowing just exactly when to place the mulch on the strawberry bed can be pretty tricky.  You don't want to cover the plants with mulch while they are still actively growing as it can cause mold and rotting to occur.  The strawberry plants should be exposed to cold temperatures long enough to go through a "hardening off" process which makes them less vulnerable to the freeze and thaw cycles of winter and to crown rot.  They should not be exposed to prolonged periods of temperatures below 20 degrees and temperatures in the low teen's can kill the flower buds and even the crown of the plant pretty quickly. 

As a rule of thumb, once the first half inch or so of soil is frozen, or when the temperature is consistently dipping into the mid-20's, it's time to get the mulch out.  Here, this can happen as early as mid October, or as late as early December.  This year, it happened in mid-November.  We had a cold snap that froze the ground and started the actual temps dipping dangerously low.  Fortunately, Mother Nature cooperated and last Saturday provided us with an absolutely beautiful day - sunny and temperatures in the low 40's - to work outside.  We dug out the pitch forks and wheelbarrows and went to work.

Three to four inches of straw will settle to two to three inches.

I use loose, clean straw for my mulch, but you can also use shredded newspapers, coarse sawdust, pine needles, or row cover fabric.  The important thing is to not use anything that will compact and form a mat over the strawberry beds. suffocating the plants.  I prefer straw, because while it settles enough to create a strong, protective blanket, it doesn't mat down into a dense covering.  In the spring, I can rake the straw into the walkways between the strawberry rows and use it for summer mulch to keep the weeds down.  That saves me a lot of removal effort and makes the summer mulching easier, and I am a big fan of anything easier.

The straw should be spread thickly enough so that after settling, there is still a two to three inch covering over the plants.  Raised bed plantings need to have a four to six inch layer of mulch to have adequate protection. If wind is likely to blow the straw around, a piece of chicken wire or other lightweight material can be laid over the top of the straw.

Once the mulch has been placed, the last job of the season is done, and I can go curl up by the fireplace with a good book and a spot of tea.

In honor of Thanksgiving, this will be the only blog article published by Wiese Acres this week.  We will be spending Thanksgiving in my hometown, with my sisters, brothers, aunts, uncles, nieces, nephews, in-laws, and friends.  It will give us time to reconnect with folks we don't see nearly enough in these busy lives of ours, and help us to reflect on and be thankful for our many, many blessings.