Benefits of Mulching
o When applied correctly, mulch has the following beneficial effects on plants and soil:
o Mulches prevent loss of water from the soil by evaporation.
o Mulches reduce the growth of weeds, when the mulch material itself is weed-free and applied deeply enough to prevent weed germination or to smother existing weeds.
o Mulches keep the soil cooler in the summer and warmer in the winter, thus maintaining a more even soil temperature.
o Mulches prevent soil splashing, which not only stops erosion but keeps soil-borne diseases from splashing up onto the plants.
o Organic mulches can improve the soil structure. As the mulch decays, the material becomes topsoil. Decaying mulch also adds nutrients to the soil.
o Mulches prevent crusting of the soil surface, thus improving the absorption and movement of water into the soil.
o Mulches prevent the trunks of trees and shrubs from damage by lawn equipment.
o Mulches help prevent soil compaction.
o Mulches can add to the beauty of the landscape by providing a cover of uniform color and interesting texture to the surface.
o Mulched plants have more roots than plants that are not mulched, because mulched plants will produce additional roots in the mulch that surrounds them.
Types of Mulches
There are basically two types of mulches: organic and inorganic. Both types may have their place in the garden.
An organic mulch is a mulch made of natural substances such as bark, wood chips, leaves, pine needles, or grass clippings. Organic mulches attract insects, slugs, cutworms and the birds that eat them. They decompose over time and need to be replaced after several years.
Inorganic mulches, such as gravel, pebbles, black plastic and landscape fabrics, do not attract pests and they do not decompose, they do not provide eathworm friendly "homes", they do not add anything to the soil, and Hey....... are they really helping the environment??? I know, I know we are re-cycling....( I still like the organics better....can You Tell!!)
Organic Mulch Materials
A 2- to 3- inch layer of pine bark is good for weed control. Pine bark makes an attractive, usually dark-colored mulch. It can be purchased in various particle sizes, from shredded to large-sized particles, called nuggets. Large pine bark nuggets float in water and may not stay in place during a heavy rain. They may also attract termites and other insects.
A 2- inch layer of pine needles makes an excellent mulch for acid-loving trees and shrubs. This mulch is very attractive and allows water to penetrate easily.
Shredded Hardwood Mulch
This mulch is good at suppressing weeds. It does not wash away easily. It decomposes relatively slowly, and it is very attractive.
One of my favorites has a fragrant aroma and is said to be a natural insect repellant.
This material contains bark and pieces of wood of various sizes and makes attractive mulch. A 2- to 3- inch layer of wood chips provides good weed control. Small wood chips decompose very rapidly using nitrogen from the soil, which needs to be replaced by nitrogen fertilizer. Wood chips may attract termites and other insects.
Pecan shells make a long-lasting, attractive, dark brown mulch that is effective in retaining moisture in the soil and can even help lower the soils PH in some instances. Availability is usually limited to areas where pecans are processed.
Inorganic Mulch Materials:
Gravel, Pebbles and Crushed Stone
These materials are permanent and are best used for permanent plantings such as foundation plants. A 1- inch layer of small rocks will provide good weed control. Do not use them around acid-loving plants since the rocks may add alkaline elements and minerals to the soil. These materials reflect solar radiation and can create a very hot landscape environment during the summer months.
Landscape Cloth or Woven Ground Cloth
Materials woven of fabric, plastic or paper are available in various lengths and widths. The materials are treated to resist decomposition. Unlike plastic films, woven materials allow water and air to move through them. They are very effective in controlling most weeds, although some grasses may grow up through the holes in the fabric. Landscape cloth needs to be fastened down so it will not be pushed up by perennial weeds. Better moisture, temperature and weed control will be obtained by adding several inches of another mulching material on top of the landscape cloth.
Ground Rubber Tires
Mulches made of ground rubber tires do not decompose and therefore, never need to be replaced. The use of ground rubber tires is relatively new and its effectiveness as a mulch is still being evaluated, but it is a great cover for play areas.
Where to Use Mulch
Mulching is a very important practice for establishing new plantings, because it helps to conserve moisture in the root ball of the new plant until the roots have grown out into the surrounding soil. The growth rate and health of trees and shrubs increases when there is no competition for water and nutrients from weeds. Mulch also helps to prevent tree trunk injury by mowers and trimmers. Newly planted trees require a circle of mulch 3 to 4 feet in diameter, “note” keep the mulch from touching the base of the tree (keeps the bugs and moisture down). Maintain this for five years. Mulch entire beds of shrubs, trees, annuals, herbaceous perennials and ground covers.
Mulch can also be used to cover trails, driveways, and play and natural areas.
Light-weight mulch such as dried grass clippings and pine straw can be used temporarily to cover low-growing tender plants to protect them from frost injury.
When and How Often to Mulch
The best time to mulch new plantings is right after you plant them. Around established plants mulch is best applied in early spring. This is when plants are beginning to grow and before weed seeds start to germinate.
How often mulch needs to be replenished depends on the mulching material. Grass clippings and leaves decompose very fast and need to be replenished frequently. Inorganic mulches such as gravel and pebbles rarely need replenishing. As the plants grow and fill in the bed areas, less and less mulch is needed.
How to Apply Mulch
Before applying any type of mulch to an area, it is best to weed the area. Spread a layer of mulching materials over the entire plant bed. Keep mulch 2 to 3 inches away from the stems of woody plants. This will prevent decay caused by wet mulch and rodent damage during the winter. Keep mulch 6 to 12 inches away from the walls of buildings.
Newly planted trees require a circle of mulch 3 to 4 feet in diameter. Maintain this for at least three years. Do not pile mulch against the trunk. For established trees in lawns create a circle of mulch about 2 feet in diameter for each inch of trunk diameter. Increase the size of the mulched area as the tree grows. Try to apply the mulch at least 6 to 12 inches beyond the drip-line of the tree. Because the root system can extend two to three times the crown spread of the tree, mulch as large an area as possible.
How Deep to Mulch
The amount of mulch to apply depends on the texture and density of the mulch material. Many wood and bark mulches are composed of fine particles and should not be more than 2 to 3 inches deep. Excessive amounts of these fine-textured mulches can suffocate plant roots, resulting in yellowing of the leaves and poor growth.
Coarse-textured mulches such as pine bark nuggets allow good air movement through them and can be as deep as 4 inches.
Mulches composed of grass clippings or shredded leaves should never be deeper than 2 inches, because these materials tend to mat together, restricting the water and air supply to plant roots.
How to Calculate the Amount of Mulch Needed
To determine how many cubic feet of mulch is needed, you need to calculate the surface area and the desired depth of coverage. There are 27 cubic feet in a cubic yard. One cubic yard will cover a 324-square-foot area with an inch of mulch. Figure out the square footage of your bed, that is the width times the length for square or rectangular shaped beds. The square footage of a circular bed is the distance from the middle of the circle to the outside, multiplied by itself and then multiplied by 3.14 (which is pi).
Multiply your square footage by the depth desired (in inches) and divide by 324 square feet. This will tell you how many cubic yards you will need.
(Thank You Very Much.... Clemson University for your Contribution :))