Experienced gardeners know that mulch is a necessity in the garden all year long. Mulch provides many important services to the garden, including temperature regulation, moisture retention, drainage, weed control, soil improvement and aesthetic appeal. In order to get the best mulch coverage for your garden, determine the size, shape, depth of coverage and plant types of the area you would like to mulch. If you choose an appropriate type of mulch and accurately calculate how much you will need, you'll end up with the best mulch coverage for your needs.
In the winter months, mulch protects the root systems of plants from exposure to freezing air temperatures, and in the summer, it provides a cooling buffer from the sun and prevents moisture evaporation. This is especially helpful for plants that have fragile or shallow root systems, such as flowers, vegetables or bulbs waiting for their blooming season. Mulch coverage is also useful for areas that do not receive much rain, because it acts as a sponge and slowly releases moisture to roots. Conversely, in areas that tend to flood because of compacted soils or rainwater runoff, mulch can be mixed into the soil to improve air flow and drainage.
Gardeners use mulch around new plants to suppress the growth of invasive weeds, which rob the soil of nutrients and moisture. Plenty of mulch coverage will ensure easier weed removal, because the roots will be more shallow and easier to pull out of the ground. Mulch is also used to add essential nutrients back into the soil, especially around plants that have specific nutrient needs. It is always a good idea to research the plants you will be mulching before selecting the material used for mulch coverage. For example, acidic mulches, such as pine needles, can be used around azaleas and other acid-loving plants, reducing the need for fertilizers and improving the health of the plant.
Both organic and inorganic materials are used for mulch. Mulches made from organic materials include pine bark or needles, straw, hardwood chips, pecan shells and recycled yard waste such as grass clippings or leaves. Inorganic mulches can be gravel, crushed stone, pebbles, plastic sheeting, landscaping cloth such as burlap, foils or recycled ground rubber. Organic mulches will decompose over time and improve the soil, but they can attract certain insects and will need to be replaced periodically. Inorganic mulches will not break down and will therefore not need to be replaced as often.
To determine the amount of mulch needed for coverage, measure the area of the space to be mulched. For rectangular shapes, multiply the length by the width. For triangular shapes with a right angle, multiply the length of the sides that meet at the right angle and divide in half.
Circular-shaped areas can be found by measuring halfway across the center of the area to get the radius, then multiplying that number by itself. The resulting number should then be multiplied by 3.14 to determine the area. If your garden is irregularly shaped, you can try breaking down the shape into several regular shapes to estimate the total area.
After the area of the space is determined, you will need to decide on the depth of the mulch coverage. This is largely based on the type of mulch you plan to spread. Mulches with a fine texture, such as grass clippings or chipped wood, should never be deeper than 2 inches (5.1 cm), because they can compact and prevent air and moisture from reaching the roots. Coarse mulches, such as gravel or pine bark, can be as deep as 4 inches (10.2 cm) because they allow for plenty of air flow and drainage. Multiply the area of your garden by the desired depth to determine the total cubic area that needs mulch coverage, which will allow you to determine how many bags of mulch you'll need to buy.
After you have determined how much and what kind of mulch to buy, be sure to prepare the area well. Rake out loose material and weed it thoroughly. In sloped areas, it might be helpful to create a border with bricks, rocks or another material to prevent mulch from washing away. Spread the mulch evenly around plants and trees with a mulch fork or rake, and replace the mulch seasonally or as necessary to ensure proper coverage.