Winter Protective Mulch

A mulch designed to protect tender plants in the winter is not the same as the mulch you put down to suppress weeds and keep moisture in the soil. The latter is usually finely chopped leaves, bark or other wood, and it works by forming a thin but fairly tight layer on top of the soil. This shield keeps the sun from triggering the germination of weed seeds, and prevents moisture from evaporating out of the soil.

But a winter protective mulch is just the opposite – it should be light and fluffy, allowing for plenty of air spaces. Air is a great insulator….think of a down comforter that keeps you toasty at night. The tiny spaces of air prevent the warmth of your body from escaping quickly because the heat is held in those small spaces in the down. So it is with a winter protective mulch. You want it to slow how the air moves to and from a plant. Most plants don’t generate heat like human bodies do, but the still air that is held around plants isn’t as cold and the wind doesn’t carry moisture away from plants that are covered.

Two of the best winter protective mulches are salt marsh hay and pine boughs. Both should be put around tender plants sometime in December, depending on the weather.

Winter protection should be removed from plants sometime in March; if left on too long in the spring the growth under the mulch can become accelerated, and this will be vulnerable once the mulch is taken away.

Once winter is over salt marsh hay can be used in vegetable gardens or put in the compost.

It’s smart to pick up salt marsh hay in November but wait to spread it until late December or early January. Store it somewhere dry if possible so that if it rains and then gets cold you won’t be trying to spread a block of ice onto your plants.