Mulches can be used to prevent weed germination and growth, and ultimately reduce time and labor required to remove weeds. Organic mulches allow some flexibility in fertilizing and watering since they can be raked back from the plants. They should normally be applied uniformly three to four inches deep around the base of the vegetable plant. Do not mulch with straw containing weed seeds. If straw contains weed seeds it should be moistened throughout, kept moist until the weed seeds germinate, and then air dried several times to kill germinating seedlings.
Black plastic is the most frequently used inorganic mulch.
Clear plastic is not recommended because it does not exclude the light that weed seeds need to germinate. Gardeners should make sure there is adequate moisture in the soil before any mulch is applied, especially plastic films. It is also necessary to apply most of the fertilizer required by the plants before the plastic is installed. There are also several durable weed fabrics that are very effective in weed suppression. They are capable of lasting up to 20 years or more when covered with soil.