What is Soil Health?
You may be hearing the term “soil health” more and more lately. But what is it? As defined by the Natural Resources Conservation Service (NRCS), soil health is “the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans.” This ecosystem is comprised of a multitude of essential and different organisms: insects, bacteria, fungi, and invertebrates. These organisms help improve soil structure, cycle nutrients, create pore spaces within the soil, and increase soil fertility. For more information on soil organisms, see Why Does Soil Health Matter? Starting with Soil Organisms.
Testing your soil by an accredited laboratory will give you the most accurate results regarding soil nutrient levels, organic matter content, and pH. Clemson University’s Agricultural Services Laboratory handles all the soil testing for South Carolina residents. The equipment at the laboratory is specifically calibrated for South Carolina soils. For more soil testing and fees information, see Clemson Ag Service Lab: Soil Testing.
Healthy, dark-colored garden soil with an open structure due to high organic matter content.
Bob Polomski, ©2023, Clemson Extension
Organic Matter
Adding a 2 to 3-inch layer of organic matter (OM) over your existing soil can help balance and restore your soil’s health. OM can neutralize your soil’s pH, improve drainage, replenish nutrients, and provide aeration. Plants tend to do best in loamy-type soils, which are slightly fluffy in texture. You are helping to create that over time with OM. For more information on organic matter, see The Role of Organic Matter in Healthy Soils.
Organic composts, plant residues, animal manures, or worm castings are high in organic matter and perfect to add to any garden space. A layer can be added to garden rows or beds in the Fall to improve structure and help insulate plant roots. A layer can also be added in the Spring to replenish nutrients and soil structure. Always use appropriately cured compost so as not to spread pathogens and diseases into your growing space. For more information on composting, please visit HGIC 1600, Composting.
Keep Soil Covered
Bare soil can take a beating from the elements. Wind, hard rain, and flooding can displace your valuable topsoil. Keeping soils covered with mulches or straw can help keep your soil in place. Covered soil also has the benefit of less drastic temperature fluctuations and less water loss. The sun’s hot rays can evaporate water from the top layer of soil rather quickly in the Summer, meaning you will have to water more frequently. When the soil is insulated with a layer of straw or mulch, it will dry out slower and not be as prone to heat and freeze issues.
Mulch can also help improve soil quality and structure while reducing weed pressure. Be sure your mulch is not dyed or treated with chemicals before adding it to your garden space. Hardwood mulch works better than pine mulch because pine is acidic and can acidify your soil’s pH over time. Also, fresh hardwood mulch can contain high amounts of tannic acid; make sure to use well-composted hardwood mulch. For more information, see HGIC 1604, Mulch.
Rotate Crops
Season-to-season crop rotation can help promote better overall soil health. Different plant species require different and varying levels of nutrients. For example, peas and beans help to add plant-ready nitrogen into the soil, while tomatoes and corn are heavy nitrogen feeders. A general rule of thumb and easy way to remember rotations is Fruit (solanaceous and cucurbit families), then Root (potatoes, carrots, radish, parsnip), then Leaf (spinach, lettuce, kale), then Legume (beans and peas).
Root vegetables help by breaking up the soil and aerating the growing space. Leafy greens can help insulate the soil during frosts, reduce water evaporation from the soil, and improve microbial activity close to the soil’s surface. Fruiting vegetables aerate the soil and improve drainage, adding more organic matter at deeper levels. Culling your plants at the soil surface is essential, leaving the roots in the ground (with root vegetables being the exception). As the roots die off, new pore spaces are created in your growing space. This aids in better drainage, aeration, and organic matter content. For more information, see HGIC 1330, Crop Rotation.
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