With our first snow last week, it may seem like the garden has gone to sleep for the winter. In reality, it is still very active as all the soil organisms and plants continue to get ready for the real winter.
The temperature about 6 inches into the soil is still about 40 degrees. Roots on many plants are still growing slowly using stored energy. Fall planted blubs are sending out roots so they will be ready for the sudden burst of energy they will need in the spring.
Soil organisms like worms, bugs, fungus and bacteria are still actively breaking down organic matter in the soil, especially if you recently tilled some leaves or other green matter into your garden. If you made a new batch of compost with your fall leaves and the last mowing of grass, the bacteria are having a field day. Stick a thermometer or even your hand into the pile and feel how warm it is. If it’s really hot, turn it and watch the steam rise into the cold air.
As it gets colder, the earthworms and other soil-dwelling creatures will migrate deeper into the soil below the frost line where they continue to feed and move about. Some will go into hibernation until it warms up. Other critters like gophers and mice retreat to grass-lined nests and food stores 1 to 2 feet underground. They might forage out on a warmer day but will retreat into their burrow as it gets cold again.
The trees and shrubs lost their leaves just in time to avoid getting loaded down by the wet snow and broken. The leaf fall signals that the plants are in the final stages of going dormant and are reducing the amount of moisture in their cells. Moving moisture out of cells reduces the potential of freeze damage and dieback when it really gets cold. This process takes a few weeks and each plant does it on its own timeline. As a result, a severe cold snap between now and mid-December can damage even the hardiest of trees. To my recollection, over the past 30 years it’s been these early severe cold snaps that have done the most lasting damage.
If you are storing winter vegetables like carrots and potatoes in the ground, wait until the ground freezes before you cover them with a foot of straw or pine needles and a tarp. These vegetables can stand being very close to freezing for an extended time but they can’t tolerate going through many freeze-thaw cycles. By putting the thick cover over the crop after it gets cold, you reduce their exposure to temperature shifts. The tarp keeps the cover material dry. When you want to dig some carrots dig under the mat and then replace it. One word of warning though: Those mice and gophers may find your stash and enjoy a feast at your expense. Been there, done that.