Practice No. 15. Use Mulch
Visualize soil etched with cracks, encrusted, parched, devoid of life. So forlorn, insects won't even traverse its expanse or dwell beneath. Cracking salt crystals or dried clay flakes is noticeable when stepping on the hard surface broken with fissures. Imagine running along the sandy upper edges of a beach, leaving footprints inches deep. A windy gust moves and shifts the dunes or sends the particles skyward. Dull, lifeless, whitish granules of compacted earth scooped up used to lay the foundation of roads. This is soil without mulch.
Now envision the soft, springy, humusy forest floor teaming with moisture occupied with the lives of mosses, ferns, lichens, perennials from tiny flowers to the giants of the plant world, trees. Or soothing vistas of the blending of billowy grass with a rainbow bloom of wildflowers in the forest's clearing, birds tweeting, bees buzzing and and the pleasant, soft flutter of butterflies.
The difference between these two scenarios is mulch. A leaf blows by in the wind and is laid to rest on the earth, followed by a drop of rain trapped and protected by the leaf. Decay sets in, fostering microbes at the junction of leaf and soil. A gust of wind drops a seed that germinates with another drop of rain and ray of sunlight encouraging a sprout, then stem, leaves and flower. By autumn's end, leaf and seed have dropped to begin the cycle yet again, followed by countless other leaves, raindrops and seeds. Over millenniums, soil filled with organic life sustaining nutrients is gradually formed.
Benefits of Mulch
Mulching, one of earth's sustaining practices, is the easiest of the practices in creating organic landscapes, providing direct and immediate benefits.
- Gradual building of topsoil through decomposition of organic matter
- Increases the root zone of plants.
- Conserves moisture by slowing evaporation.
- Moderates soil temperature, avoids extremes and rapid temperature change.
- Prevents soil crusting, allows and increases water in-soak and aeration.
- Prevents rain from splashing soil on the lower leaves of plants, keeping their pores open.
- Prevents compaction on walkways, throughout gardens and beds. Lawns mowed with a mulching mower have a small degree of mulch added with each mowing.
- Inhibits seed germination.
- Organic mulch helps feed and increases the beneficial soil life at soil surface.
- Mulch slows or prevents erosion.
Organic and Inorganic Mulch
Mulch can be either organic or inorganic depending on the plants and purpose. Two to four inches provides an adequate cover, replenished when needed. Some examples of organic mulches are straw, grass clippings and healthy chopped plant debris, shredded bark, wood and bark chips, pine needles, compost, humus, cottonseed hulls, alfalfa pellets, cocoa bean hulls (toxic to dogs), pecan shells, peanut hulls, chopped and crushed corncobs, mushroom compost, shredded newspapers or other papers (depending on ink used), leaf mold, chopped leaves, and living plants. If you're an impatient composter, "almost compost" makes excellent mulch. Rubber mulch, though containing carbon and thus considered “organic” should not be used. Toxic chemicals leach out into surrounding beds as it heats up in the summer.
Be wary of herbicides in hay, straw, manures and compost as mentioned in the section on compost. Refer to the bulletin by North Carolina State University Cooperative Extension on persistent herbicide carryover.
In gardens and fields left fallow, planting a cover crops serves the purpose of both mulch and quick boost of nutrients when tilled in early spring. Cover crops of hairy vetch, alfalfa, clovers, annual rye or buckwheat or other annual grasses or legumes are also used for several seasons in building poor soil.
Some gardeners dispense with applying a cover of mulch, instead rely on the spread of the plants themselves to take on the role of mulch. This is might seem fine during the growing season in some climates, soils in our hot, windy climate need an actual mulch covering, in my opinion.
Some inorganic mulches are crushed gravel and granite, small stone, lava or granite rock, decorative and colored stones, sand, plastic, or crushed brick and crushed, tumbled glass. Inorganic mulch has decorative benefits as well and can be used to portray water and create patterns. Xeric, drought tolerant, and drought requiring plants favor inorganic mulch. These water-thrifty plants are more susceptible to root rot if kept too moist, up close at their base.
Read more about mulching, this basic principle of successful gardening.