Mulching trees and shrubs can be a good thing but too much mulch can kill roots and eventually plants by reducing soil air(oxygen). When you pile mulch high and deep it causes root death through oxygen deprivation, or the production of toxins that kill roots.
One of the primary reasons for mulching in all seasons is to retain moisture around the plant , stabilize or even cool the soil, and reduce weeds. Research has shown that fine mulch needs to be no deeper than two inches and a bulky mulch 4 inches to eliminate light needed for weed seeds to germinate and provide these other benefits. To figure out how much mulch you need simply multiply the area you wish to mulch by the depth of the mulch and then divide this number by 12. If you want to calculate cubic yards divide by 324 rather than 12.
Another reason to apply mulch is for winter protection. This is usually done after the soil has cooled or frozen. All season mulch is applied after the soil warms up a little in the spring or of course any time later. Wait until the soil is moist to apply for moisture retention.
Mulches may have other imperfections. Mulch is a great place for overwintering insects, diseases, and rodents. If mulch gets too dry it may actually repel watering. Each mulch has advantages and disadvantages that will be discussed in a future blog.
Jerry Frecon
Agricultural Agent
