Living Soils: The Key to Healthy Gardens
“The soil is the great connector of lives, the source and destination of all. It is the healer and restorer and resurrector, by which disease passes into health, age into youth, death into life. Without proper care for it we can have no community, because without proper care for it we can have no life”― Wendell Berry, The Unsettling of America: Culture and Agriculture.
We sometimes think of soil as an inert substance, but in reality, it is teeming with life. It is estimated that a teaspoon of soil contains up to one billion bacteria, yards of fungal filaments, and scores of nematodes and protozoa. This web of organisms and microorganisms are essential to long-term soil health. The biological makeup of the soil is crucial for forging pathways that help plants to make the most of the chemical and mineral components found deep underground. If you have a garden, you likely know the importance of adding compost and amendments to the soil each year to improve fertility. However, it is also crucial to maintain the living ecosystem below ground. You can have rich soil, but without the organisms found in the soil, plant roots will be unable to take up the nutrients. Whether you are vegetable gardening, planting a tree, or creating a potted arrangement, using biologically living soil will help your plants to thrive.
So what is the function of this underground ecosystem? Let’s start with the big stuff. Earthworms and insects can be easily found in healthy garden soil. They consume organic matter on the ground level-chewing the larger pieces of compost to break it down. Earthworms move through the soil, creating pathways below ground that aerate and improve soil structure. Their movements also move soil from deep underground closer to the surface, essentially mixing the nutrient stew that plants rely on. Their gut bacteria chemically alters the makeup of the soil, creating more available nutrients for plants. Arthropods and micropanthropods, which are small insects, help to break down pieces of organic matter, and control bacteria and insect populations.
If you look closely, you’ll be able to see earthworms and insects in your garden. However, there are many more microorganisms in healthy soil that cannot be seen by the naked eye. Nematodes are tiny worm-like organisms that break organic matter in the soil down further. Bacteria and actinomycetes are mostly found in the upper 3” of topsoil, and are most active when soil temperatures are between 70-80 degrees Fahrenheit. They recycle plant material with the help of beneficial fungi.
Bacteria often form symbiotic relationships with plant roots, allowing for more efficient nutrient uptake. One of the more researched forms of this relationship is found with the nitrogen-fixing bacteria Rhizobiaceae, α-Proteobacteria. While nearly 80% of the Earth’s atmosphere is made up of nitrogen, it is not in a form that plants can consume. This nitrogen-fixing bacteria forms clusters in the rhizosphere, around the plant roots. As the plant respirates and inhales nitrogen from the air, nodules of bacteria convert the nitrogen into ammonia, which the plant can then absorb into its tissue. Without this beneficial bacteria, leguminous plants would not be efficient “nitrogen fixers” in the soil. There are also a number of non-leguminous plants, including beech, birch, roses, and alders that use these rhizomal bacteria to convert atmospheric nitrogen into a usable form.
Another microorganism that can be found in the rhizosphere are fungi. Fungi have co-evolved with the plant world for millennia; the oldest fossilized fungus is thought to be over one billion years old. Mycorrhizae fungi have formed symbiotic relationships with roots, clustering in the rhizomal zone to exchange nutrients with plants. Long filaments of mycorrhizae fungi form networks and pathways, acting as an extension to plant roots to increase surface area and nutrient absorption. Sometimes called the “wood wide web,” this network stretches throughout the forest, fields, and gardens, with yards of tiny filaments that act as chemical and nutrient highways.
When establishing a garden, it is important to use soil that not only is rich in nutrient and organic matter, but one that will sustain a healthy ecosystem for years to come. All EarthMix® soil blends and composts are created using proven recipes that foster rich microbial growth. Many soil mixes and amendments contain added beneficial microorganisms, in order to give potted plants or garden soil a boost to foster greater nutrient uptake naturally. EarthMix® Garden Products are never sterilized, using the natural process of composting to kill weed seeds while fostering beneficial biological growth. Give your garden a head start with biologically living soil this spring.
This 60-minute documentary features innovative farmers and soil health experts from throughout the U.S. It was directed by Chelsea Myers and Tiny Attic Productions based in Columbia, Missouri, and produced by the Soil Health Institute through the generous support of The Samuel Roberts Noble Foundation.