During the fall-winter and summer months the topic of mulching tends to pop up quite frequently, and for good reason.
Mulch is a wonderful help to keep plants warm and snug in the winter, and cool in the blazing hot of summer.
It saves water, keeps plants from freezing, cuts down on weeding, and depending upon what kind of mulch you use, it can add nutrients to the soil.
While this is all interesting, the most common question received is, "When mulching, how much do I use?."
Well, how thickly you lay mulch depends on the size of its particles.
Thin, fine particles like compost or finely shredded bark are best laid only 2 inches (5.1 cm) to no more than 3 inches (7.6 cm) deep around most plants and trees. If you put down a thicker layer than that, you risk reducing oxygen to the roots.
If the particle size of your mulch is larger, like straw, pine needles, chunks of bark, or rock, they can be applied up to 4 inches (10 cm) deep. The larger spaces between the chunks allow more air and light in, so you will need a thicker layer for effective weed control, water conservation, and protection from cold.
Warning: Whenever you mulch anything, be super careful to leave some space around the plant crown, or tree base. If you pile any kind of mulch up against the crown, you will rot the plant out and it will die.
So leave a 1 to 2 inches (2.5 to 5.1 cm) of breathing room near the stem or base of the plant and you'll be just fine.