Mulching is the practice of applying a layer of material to the soil surface around plants. Mulch conserves soil moisture by reducing evaporation, moderates soil temperature, suppresses weed germination, prevents [[Erosion Control]], and adds organic matter as it decomposes. A 5 to 10 centimeter (2 to 4 inch) layer of mulch is generally recommended for most garden applications. Mulch can be organic, such as wood chips, straw, or leaves, or inorganic, such as landscape fabric or plastic sheeting.
Organic mulches decompose over time and contribute to [[Soil Composition]] by increasing organic matter. Wood chips and bark mulch are long-lasting, decomposing over 2 to 4 years, and are ideal for pathways, shrubs, and trees. Straw and hay break down more quickly, within one growing season, and are well-suited to vegetable gardens and strawberry beds. Grass clippings provide a nitrogen-rich mulch that decomposes rapidly and should be applied in thin layers to avoid matting and odor. Compost can be used as a fine-textured mulch that feeds plants directly as it breaks down.
Black plastic mulch warms the soil, making it useful for heat-loving crops such as tomatoes, peppers, and melons. Red plastic mulch has been shown to increase tomato yields in some studies. Landscape fabric allows water and air to pass through while blocking light for weed suppression. Gravel and pebble mulches are used in xeriscaping and around perennials where long-term weed control is needed without frequent replenishment.
In vegetable gardens, a straw or leaf mulch applied after the soil has warmed in late spring reduces the need for watering and weeding throughout the growing season. In perennial beds, a 5 to 8 centimeter (2 to 3 inch) layer of wood chips provides long-term weed control. In tree and shrub plantings, a doughnut-shaped mulch ring kept away from the trunk prevents moisture-related diseases. [[No-Till Gardening]] relies on a continuous mulch layer as its primary management tool.