Life Underground: How Various Soil Organisms Deliver Healthy Grass
The soil beneath your lawn is teeming with life, most of these soil organisms are invisible to us but all of it vital to growing thick, healthy grass.
Consider this: There are more living things in a teaspoon of healthy soil than there are people on Earth. These billions of bacteria, protozoa, fungi, and wormlike microscopic nematodes are the base of the food chain in soil. Like the microbes in your digestive tract, soil organisms break down fertilizer so grass can absorb its nutrients. Let’s dig in and get to know the players and how to keep them serving your lawn’s needs.
Key job: Each of the dozens of different types of bacteria in the soil have a unique role. The one that is especially crucial to your lawn is breaking down decaying plant matter into nutrients that grass can take in most easily.
Critical need: These microscopic soil organisms thrive on a constant supply of fresh organic matter: grass clippings, shredded leaves, and most of all, compost. Spread a half inch of finely sieved compost on your lawn in fall and spring to keep the bacteria activated and feeding the grass.
Know this: Plants’ roots release compounds into the soil that attract the bacteria most beneficial to the plant; in effect, the plants are farming bacteria for their own needs, say soil scientists at the United States Department of Agriculture’s Natural Resources Conservation Service.
Key job: Mycorrhizae (pronounced “my-core-rise-ah”) are important fungi that colonize grass’s roots, help it metabolize phosphorus, and bring other nutrients to the roots.
Critical need: Protect the fungi in your soil by using only organic fertilizers. Synthetic plant foods tend to be high in salt, which dehydrates the soil and fungi.
Know this: Scientists have found a fungus in Oregon that covers 2,200 acres and may be at least 2,400 years old. It is thought to be the world’s largest living thing.
The Proto Types
Key job: Protozoa are one-celled organisms that prey on bacteria, keeping the good bacteria population in balance and fending off pathogens, those bacteria that cause plant diseases.
Critical need: Protozoa require oxygen to keep eating and reproducing, but it’s often in short supply in lawns at recently built homes, where heavy clay soil has been compacted by construction equipment. Introduce air pockets with a core-aerating machine, allowing air and water into the soil for these soil organisms and your plants’ roots.
Know this: The vampyrellid amoebae, a kind of protozoa, got its name because it makes two perfectly round holes in the cell walls of its prey, like the puncture marks from a vampire bite.
Key job: Nematodes, often called roundworms, feed on bacteria and fungi, and are food for larger nematodes. They occupy a middle niche in the food chain, but their most crucial function may be helping to move smaller microbes, which cling to the nematodes, through the soil.
Critical need: Nematodes are among the most adaptable creatures, tolerating extremes of heat and cold, drought, low fertility, compaction, and many other conditions that keep grass from growing. But these soil organisms won’t survive long where other soil fauna have been wiped out by toxic chemicals, such as herbicides.
Know this: Root-knot nematodes are pests for many vegetable gardeners, but another species of nematodes preys on grubs that damage lawns.
Key job: Tiny arthropods, insects with jointed legs and a hard exoskeleton, shred large chunks of decaying plant matter into pieces small enough for bacteria and fungi to consume. Beetles and millipedes are familiar soil arthropods, as are mites and ants.
Critical need: When arthropods don’t have sufficient fresh organic matter to shred, they turn their appetites to plants’ roots. Always recycle clippings onto your lawn to keep arthropods from chewing up your grass.
Know this: A small arthropod that lives in the soil, the springtail looks like a tiny scorpion. Springtails use their rear appendage not to sting but to catapult themselves away from danger—as far as 3 feet in one leap.
Key job: The tunnels dug by earthworms allow air, water, and fertilizer to reach deep into the soil for all the other soil-dwellers to consume. Burrowing by earthworms also mixes together all the many different components of the soil.
Critical need: Decaying leaves are just about the favorite food of earthworms. Rather than raking up all the autumn leaves from your lawn, run them over with your mower and allow them to fall back into the grass, where earthworms will feast on them.
Know this: You can buy bags of nutrient-rich earthworm castings (manure) to feed houseplants, but they are too pricey for fertilizing lawns.
How to Help These Soil Organisms
The soil-dwellers work together to break down fertilizers into nutrients grass’s roots can take up. Synthetic fertilizers are high in salts, which dehydrate the soil and the hard-working soil-dwellers. Keep your soil life healthy and the microbes active with fertilizers, such as Ringer® Lawn Restore.
Are you trying to maximize the the benefits these soil organisms deliver to your lawn? If so, we would love for you to tell us about it the next time you visit Safer® Brand on Facebook, where we’re active reaching out to the organic gardening and lawn care community. Our E-Newsletter is another helpful resource that delivers fresh articles, new product announcements and helpful links to your inbox.