Bountiful, vibrant, healthy plants come from healthy soil—organic, living, and free from toxic chemicals or fertilizers. But how do you determine the health of your existing soil and how to improve it to maximize your growing efforts?
Soil Health Pyramid™
For home gardeners, we’ve developed the Soil Health Pyramid™ to simplify this process. It focuses on the three most important aspects of soil health: Composition, Nutrients, and Microbiology.
Soil is made of air (25%), water (25%), minerals (45%), and organic matter (5%). Healthy, living soils have adequate air, water and nutrient holding capacity as well as sufficient porosity for air and water to move freely about.
The texture of your soil is primarily driven by your geographic location and is one of the only properties of your soil that you can’t change. The differences in soil texture dictate it’s ability to hold air, water and nutrients and plays a role in pH. The USDA has categorized the soil textures of all locations in the US. The USDA Soil Texture Triangle can help you determine your soil type.
Soil pH: Soil pH measures relative acidity on a scale of 0 to 14. A pH of 0 to 7 is acidic, while a pH of 7 to 14 is alkaline. Plant and soil organisms have a preferred optimum pH of neutral or slightly below neutral. Soil texture plays a role in pH—sandy soils tend toward acid, while heavy clay soils tend toward alkaline. Keeping soil pH in balance is essential to proper plant nutrition and providing good fertility for your living soil. A standard soil test will indicate your soil’s pH or you can use a pH meter to test the soil in your lawn and gardens.
How much organic matter is feeding your soil? Organic matter is anything living or once living that provides basic food to plants and living organisms. It works like a sponge, capturing and holding on to resources like water and nutrients. Organic matter changes soil structure and builds friable, loose soils.
Remedies and Inputs:
- Measure the pH level in your soil. Bring your soil pH to neutral or slightly below neutral by adding lime or gypsum.
- Add organic matter to your soil using mulch, compost, peat and manures. A healthy soil should contain roughly 5% organic matter.
The following macro and micronutrients are necessary for plant growth:
The primary macronutrients for plant growth are nitrogen (N), phosphorus (P), and potassium (K).
- Nitrogen promotes leaf development because of its role in the plant’s coloring and chlorophyll.
- Phosphorus plays a big role in the growth of roots, blooming and fruiting.
- Potassium plays a part in root growth as well as in stem development.
Secondary nutrients include calcium, magnesium and sulfur that also contribute to plant growth.
Micronutrients include chlorine, iron, boron, manganese, zinc, and copper.
All macro and micronutrients contribute to plant growth and health, and should be present in your soils. A standard soil test will indicate the presence of these important nutrients in your soil, and identify deficiencies that need to be remedied.
Remedies and Inputs:
- Apply organic time-released fertilizer. Ask your home & garden professional to recommend a fertilizer that is best suited to the plants you are growing.
- Mix one or more of the following organic materials into your soil: alfalfa meal, bone meal, feather meal, fish meal, kelp meal, rock phosphate, limestone, dolomite limestone, gypsum, eggshells, oyster shells or coffee grounds.
Living soil contains diverse, rich microbial populations of bacteria, fungi, and microorganisms that consume and convert nutrients and minerals to highly plant available compounds. There are more soil microorganisms in a teaspoon of healthy soil than there are people on earth. Millions of species and billions of organisms—bacteria, algae, microscopic insects, earthworms, beetles, ants, mites, fungi and more—represent the greatest concentration of biomass anywhere on the planet. Microbes, which make up only one half of one percent of the total soil mass, are the yeasts, algae, protozoa, bacteria, nematodes and fungi that process organic matter into rich, dark, stable humus in soil. They are essential to soil health and a primary contributor to plant health.
Microbiology is the new frontier of modern agriculture. Emerging regenerative farming practices are designed to rejuvenate soil microbiology and promote biodiversity improving soil health and fertility. Increasingly, growers are focused on improving the overall quality of their crops to realize higher prices and to differentiate their products in the marketplace. Improving soil microbiology can increase yields and improve quality.
Remedies and Inputs:
- Incorporate regenerative farming methods into standard operating procedures—cover cropping, crop rotation and no tillage.
- Build soil organic matter by adding compost, vermicompost and manures.
- Inoculate soil with bio-stimulants like vermi-extract, liquid composts, and mycorrhizal fungi.
For commercial growers and farmers, and perhaps the most ambitious and experienced gardeners, soil testing is the first best step to fully understanding the health of your soil. We recommend conducting a standard soil test that examines soil composition and nutrients, and a soil microbial test that analyzes the living microorganisms in your soil. These tests provide a baseline for the overall health of your soil, and enable you to begin utilizing inputs to reduce or remedy deficiencies.
We have developed relationships with Regenerative Ag Lab and Biome Makers to provide comprehensive soil testing, working closely with them to develop a format that makes it easier to understand findings relative to scientifically established soil health benchmarks.
Plant tissue testing at various intervals indicates the ongoing ability of plants to uptake nutrients efficiently. Post-harvest, soil should be retested to evaluate the relative success of implemented remedies and to determine the best methods of preparing the soil for the next growing season.
Be on the look out for the Terravesco Soil Health Exam coming in 2021!