Plant growth may be slowed if organic mulches are applied when soil temperatures are still cool in early spring. Grass clippings, shredded leaves, and similar materials break down relatively quickly and can be tilled into the soil in the fall. Apply 2 to 4 inches of material around landscape plantings. These materials decay slowly and should last several years. However, it will be necessary to periodically apply additional material to retain the desired depth.
Black plastic is an excellent mulch for the vegetable garden.
The edges of the plastic are placed in trenches and covered with soil. Plants or seeds are set in holes made in the plastic. Black plastic controls weeds, but it also increases soil temperatures in the spring. Warmer soil temperatures promote plant growth and early yields of warm-season vegetables. Black plastic is a poor mulch for landscape plantings.