Snow is beneficial to our gardens

The Detroit News

We got a brief taste of the polar vortex earlier recently  after a long stretch of relatively mild winter weather.

The soil in some spots in our garden never did freeze much. Earlier this month, we even discussed the idea of tilling up a new area since the soil was still not frozen. I didn’t follow through with it though.

In most parts of southeastern MIchigan, whatever frost there is in the ground is not very deep. The frost will most likely not penetrate much further even with the recent sub-zero air temperatures. It reached -13 degrees F at our place Wednesday morning just after dawn.

Fortunately, we received nearly a foot of snow before the cold air settled in. It was an extremely fluffy snow with a snow to liquid precipitation ratio of around 15:1 meaning 15 inches of snow would need to fall to equal one inch of rain, moisture-wise. Normally the ratio is closer to 10:1 or 8:1.

It seems like every winter I need to point out to someone that snow is great for perennial plants because of its insulative value. So many people equate snow with coldness that they don’t realize the importance it has when it comes to protecting plants.

Fluffy snow with all of its dead air spaces makes great insulation for the soil and will greatly reduce further ground freezing. Not only will it prevent further freezing, the insulating effect allows warmth from deep in the soil to radiate back to the surface. Compared to bare earth, snow-covered soil temperature in the upper part of the soil strata can be 30 to 55 degrees higher.

There may not be much to see in a garden covered with a foot of snow but the perennial plants are well protected from damaging sub-zero temperatures.

Farmers who grow winter wheat are always grateful for snow. Winter wheat is planted in the fall and makes part of its growth before going dormant for the winter. Those young wheat plants are easily damaged when directly exposed to very cold temperatures, especially if it is windy. But with a protective covering of snow, they can withstand an extremely cold winter.

My cover crop of winter rye would have benefited from a nice, deep layer of snow early in the winter for another reason. Because the beginning of winter was so mild and there wasn’t much snow, Canada geese visited the garden continuously eating the young rye sprouts. A covering of snow would have made it much harder for the geese to feed on the rye plants.

Snow not only keeps frost from penetrating very far, it also reduces the freeze / thaw cycle that sometimes happens in our area when the soil alternately freezes then thaws out. If that cycle occurs too many times, plants can be damaged by being heaved out of their space in the soil.

Snow of course can damage plants, especially trees and shrubs. When snow is wet and there’s enough of it collecting on the branches, the shear weight bearing down can break branches. Even then, it’s surprising how much snow weight some species of trees can take before they are damaged.

We don’t have a choice in what kind of weather gets sent our way. So if we have to deal with excessively cold weather, it’s best to do so with snow on the ground.