The best strategies for controlling weeds in the home garden and landscape include mulching, hand-pulling, using tools such as the hoe and rototiller, and preventing existing weeds from going to seed. Mulching around plants will go a long way toward reducing the ability of weeds to cause problems. Organic mulches tend to cool the soil, as well as conserve soil moisture and reduce weed germination. Materials such as chipped or shredded bark, straw, hay, grass clippings, or pine needles should be applied 2-4 inches deep and replenished as needed.
Grass clippings treated with pesticide, especially herbicide, should not be used. Plastic mulch tends to warm the soil and is best used on warm-season vegetables such as tomatoes, melons, squash, and peppers. Fabric weed barriers have been useful for reducing weed growth in permanent landscape plantings. (For more information on mulches, please see the Iowa State Publication on the subject at http://www.extension.iastate.edu/Publications/SUL12.pdf.)