Organic or inorganic materials applied to the soil surface in or around plants are referred to as mulch. Organic mulches like grass clippings, pine needles and bark provide a barrier to weeds and break down slowly, adding organic matter to the soil. Inorganic mulches, like plastic, landscape fabric, gravel or stone provide a weed barrier, prevent water loss to evaporation and often improve the appearance of gardens. Which type of mulch you choose depends on the desired effect.
Use organic mulches to keep soil cool and to prevent weeds. Grass clippings, leaves, hay, bark or pine needles are typically free and require no staking or anchoring. Ideal for seasonal crops, organic mulch decays and becomes part of the soil. Till into the soil at the end of the season to add texture and nutrients to the soil.
Choose semi-permanent mulch like landscape fabric or plastic sheeting for vegetables like tomatoes and peppers that benefit from warm soil. Landscape fabric contains tiny holes to allow water to penetrate. Plastic requires punching holes to allow water to reach the soil. Both require anchoring the ends in the soil or with landscape pegs to prevent the wind from blowing them free. Plastic or landscape fabric may last for several years if removed and stored properly at the end of the season. These are readily available in gardening stores and are relatively inexpensive.
Select permanent inorganic mulches for permanent landscaping. Crushed rock and gravel placed around shrubs and trees creates a weed-free area and highlights the plant. Typically, this mulch survives for years with little care. Expense varies with the specific mulch, but permanent mulches cost more than other forms. The advantage is that they last forever and do not typically require replacing.