Do not use straw that contains weed seeds as mulch. If the straw does contain weed seeds, water the straw until the seeds germinate and then air-dry repeatedly until the seedlings are killed. When applying the mulch in the garden soil, spread the mulch evenly three to four inches deep around the base of the vegetable. To water and fertilize the vegetables, simply rake back the organic mulch and then return it after watering. Inorganic mulches are mulches that do not decompose and most be removed from the soil.
Plastics are the most common inorganic mulches.
Black plastic is better than clear plastic because it blocks sunlight that weed seeds need to germinate. The soil must be well fertilized and watered before the plastic is applied. Weed fabrics can also be used as an effective weed suppression mulch and can last for twenty years when buried in soil. Organic mulches are mainly used in the latter part of the spring when the soil is warmer. If organic mulch is applied to cold soil, the soil warms more slowly and the vegetable growth rate is slower.