Mulches control weeds by preventing weed seed germination. Mulches effectively control most annual weeds. Perennial weeds, however, have to be controlled by alternate methods. Organic mulches include ground corncobs, lawn clippings, compost, straw, pine needles, wood chips, and sawdust. Synthetic or inorganic mulches include black plastic and porous landscape mats.
Mulch selection is based on availability, cost, durability, appearance, and ease of application.
Lawn clippings, shredded leaves and straw are excellent organic mulches for vegetable gardens and annual flower beds. Apply these materials in early June after the soil has warmed sufficiently. Plant growth may be slowed if organic mulches are applied when soil temperatures are still cool in early spring. In the fall, these materials can be tilled into the soil. These materials decay slowly and should last for several years.