The Scoop on Mulch

With the advent of spring your planting beds are likely looking a little dull and you are probably anxious to spruce things up with a fresh coat of mulch. But before you blanket those beds consider for a moment the various factors involved with this regular garden activity. 

Mulches can be found in a variety of forms from ground buckwheat hulls or shredded bark to pebbles or even ground up old tires (no joke). Mulches in our urban and suburban landscapes are employed primarily as decorative elements and as weed barriers. While these may be useful attributes there are other noteworthy benefits mulches can provide that impact the health (and beauty) of the plants living in these beds.

Water Absorption and Retention

One of the most important benefits mulch can provide is absorption of rainwater. During periods of heavy or prolonged showers water in lawn areas (and paved surfaces) will runoff rather than be absorbed. Mulched surfaces are both highly porous and are capable of storing water then used by plants as needed. At the same time, mulched areas provide a barrier to evaporation from sun and wind. These combined benefits eliminate the need for irrigation in bed areas once plants become established. Finally, in the greater scheme of things, mulch provides a vehicle for water to be transferred into the soil and ultimately to the water table helping to reduce surface flooding.

Further Benefits

In addition to maintaining soil moisture levels, the use of mulch can provide other valuable benefits. Organic mulches such as composted bark mulch (the dark, rich smelling variety), or, better yet, straight compost (comprised of leaves, grass clippings, vegetable kitchen waist, etc.) enriches the soil and over time improves soil structure. Mulches also play a valuable role in moderating extremes in temperature of the soil at surface layer where roots are concentrated. Finally, by slowing the movement of water and directing it down rather than across the ground mulch prevents water from forming streams that lead to erosion.

Living Layer

There is no better example of an effective mulch than what we find demonstrated in a natural setting. The duff layer created by years of leaf litter fallen trees and animal activity provides the ideal growing environment for most plants in our climate. A plush, insulating layer of new leaves and fallen branches rests above a moisture rich semi composted layer which intern covers nutrient rich, black compost, alive with beneficial fungi and bacteria. The plants and organisms maintain a symbiotic relationship within this environment; what is good for the plants is good for the organisms and vise versa. To truly understand the value of this life suporting layer all one need do is take a handful and inhale its sweet, refreshing aroma.