High Elevation Gardening Web Log "Blog"

Now suppose I added that application of this substance required no special equipment or, indeed, any effort at all, and that it was available to everyone absolutely free of charge. What could this wonderful substance possibly be, and why haven’t we heard about it before now? Well, in fact, this wondrous “substance” is simply snow! And while there’s nothing especially amazing about snow in Flagstaff, its many benefits to the garden may come as a surprise.

The value of snow as a natural mulch is well known. While plants and the ground are covered by a deep blanket of snow, they are protected from the bitter cold and extremely dry air that often follow a snowstorm in Flagstaff. Snow keeps the soil relatively warm as well, preventing the hard freezing at the surface which often results in frost heave and even spring bulb heave!

When the soil is frozen and broken due to freezing, it is more vulnerable in the spring to being blown or washed away. In tests conducted in Alaska, snow was found to keep temperature of the soil as much as 20 degree Fahrenheit above the permafrost and the air temperature. This relative warmth protects shallow-rooted plants, such as perennials, shrubs, and many grasses.

The warmer soil also provides a home for many beneficial insects and micro-organisms, essential to garden health. A deep layer also shelters mice, voles, and other surface-dwelling critters, whose burrows and winter activities help to break down organic debris, such as dead plants, leaves, and twigs, and convert these to rich soil.

A snow mulch also prevents the soil from drying out and, as it slowly melts, allows water to seep gradually through the soil, eventually reaching the deep aquifers. Rain water tends to run off the soil too quickly to soak down to the aquifers, so snow is essential for maintaining these ancient fresh water reservoirs.

Our atmosphere consists mainly of nitrogen (79%) and oxygen (20%), along with a variety of trace gases. As snowflakes fall through the air, they collect nitrogen and trap it on the ground, where it gradually leaches into the soil. Snow also delivers a small amount of phosphorus. As every gardener knows, both nitrogen and phosphorus are highly beneficial to plants. Norma Evans, a Master Gardener in Ontario, Canada, reports in the Peterborough Examiner on an experiment conducted at the Siberian Botanical Garden, in which a variety of food plants were watered with melted snow and ordinary water. Those watered with melted snow grew twice as fast as the others! Clearly, snow has a lot to offer.

So the next time snow falls on Flagstaff and environs, you might want to move some of it from your driveway and front walk on to your garden. Lay it gently over your plants and tuck it in around your trees and shrubs. Let's make the most of winter's gift to our gardens.

By Alice Monet
The author is a Master Gardener volunteer for Coconino County Cooperative Extension. For more information about the Master Gardener Program, call 774-1868 ext. 17 or visit our Web site: highelevationgardening.arizona.edu.