Mulch provides many benefits for a garden. First, mulch retains moisture in the soil and reduces the need for irrigation. In fact, mulch can decrease water use by an average of 25 percent. Mulch also inhibits the growth of weeds, prevents soil erosion, regulates soil temperature and enhances the natural aesthetics of a garden.
While mulch is necessary for most landscapes, there are many varieties of mulch from which to choose, and the choice can be daunting – especially for the novice gardener. Consider certain aspects of mulch to choose the right addition for your lawn and garden.
There are two basic types of mulch: inorganic and organic. Inorganic mulch such as stone and brick will conserve water and shade the soil. Inorganic mulch is resilient in diverse climates, and it does not disintegrate. However, inorganic mulch will not improve the condition of the soil. Organic mulch such as bark, wood and pine straw will also conserve water and shade the soil. In addition, it will improve the condition of the soil by increasing the fertility of sandy soils, improving the drainage of clay soils and adding valuable nutrients. But, organic mulch will eventually disintegrate and must be replaced.
The ability of the pH of mulch to alter the pH of soil is a subject of debate. Clay soils are generally resistant to change, so the pH level of the mulch may have minimal or no impact on the pH level of the soil. However, the sandy, acidic soils that are prevalent in the Fort Bragg region are more vulnerable to the pH levels of mulch. Pine straw and pine bark are solid choices for gardens with plants that prefer acidic environments such as azaleas, rhododendrons, camellias and gardenias.
Mulch is available in a variety of colors. For instance, pine bark is naturally dark while cypress mulch is naturally pale. The color of mulch is not only an aesthetic consideration, though. The hue can also have an impact on the ambient temperature of a garden bed. On a summer day, dark mulch can reach a temperature of 140 to 150 degrees, so dark mulch should be used in beds only where plants are heat-tolerant. For plants that are sensitive to heat, pale mulch is preferable.
SIZE AND WEIGHT
Aesthetically, the size of the particles of the mulch should be proportionate to the size of the plants in the garden bed. Dense mulches are best for garden beds that are located on slopes, in wet climates or in windy climates. Light mulches can wash away on slopes and tend to float during rain or wind events. Particle size and weight will affect the spread density, too. Shredded hardwood mulch with fine, compactable particles should be applied two to three inches deep. Coarse bark nuggets can be applied three to five inches deep, and loose straw can be applied up to six inches deep.
Fresh, viable mulch should have a clean aroma that is similar to the fragrance of cut wood or soil. Avoid any mulch that carries an odor of vinegar, ammonia or sulfur, which indicates that the mulch is sour. Sour mulch can damage or destroy plants.
Research the origins of mulch. Avoid mulch that contains treated, preserved, painted or stained wood – especially if you are mulching around edible plants. Such wood can contain harmful chemicals that could leach into the soil and into plants.
OTHER MULCHING TIPS …
- Research the mulching needs of your plants and mulch them according to their specific preferences.
- Choose mulch that has been certified by The Mulch and Soil Council. The certification program provides retailers and consumers with information about quality standards and truth-in-labeling practices for commercially-produced soils and mulches.
- Grass clippings and shredded leaves are common mulches but should be used with care due to the probable presence of weeds in the mulch. Grass clippings and shredded leaves also decay rapidly.
- Excessive mulching can suffocate plants. The less porous and more compactable the mulch is, the thinner it should be spread. Apply mulch eight inches from the bases of plants.
- Avoid the use of plastics in garden beds. While plastics can retain moisture and inhibit weeds, some plastics can contain harmful chemicals. Furthermore, plastics can cause excessive heating of the soil, which can be detrimental to plants.
- Mulch only when seedlings and perennials are up and green. Hasty mulching can stall the growth of plants.
- Do not work bark or wood mulch into the soil at the end of the growing season. Bark or wood mulch can compete for nutrients and cause a nitrogen deficiency in the soil.
- Generally, one cubic yard of mulch will cover a 100 square foot area to a depth of up to three inches.