STEP 10 - Earthworms
With organic lawncare, the strategy is to establish a healthy lawn that is more resilient to turf disease and droughts, and is nearly self-sustaining. Healthy turf is built upon a dynamic soil foodweb consisting of diverse microbial activity and other beneficial insects, particularly earthworms. Soil microbes and earthworms breakdown bacteria, cycle nutrients, aerate and maintain soil structure, and provide natural defenses against disease and pests. As noted by respect organic lawn care expert and author Paul Sachs, "Earthworm activity can provide aeration, improving water infiltration, and mitigating soil compaction."
Earthworms are incredibly important to reducing the thick layer of thatch that is common with chemically
-maintained lawns. An earthworm is a "shredder" type of soil organism that breaks down residue and enhances the soil structure. They feed on "plant litter" or bacteria and fungi, and their fecal pellets (called "castings") enhance the soil of your lawn. Earthworms can eat as much as their own body-weight every day, and each worm can process about 10 pounds of organic matter per year. Very healthy soil can have as much as one million worms per acre. That means on a typical suburban 60 by 100 foot plot of land can have 70,000 earthworms living and working and providing more than half-a-million pounds of highly beneficial castings to your turf.
Earthworms feed on organic matter; by adding compost and leaving the clippings when you mow the lawn, you are keeping them well fed. In addition to eating, earthworms also burrow through the soil, leaving tunnels that aerate the soil. Aeration is especially important in heavy traffic areas. For example, where kids play ball, earthworms can help to combat soil compaction, which can be a big challenge for lawns. Earthworms come to the surface of the soil to feed at night, pulling leaves, grass clippings, seeds and other plant matter into their burrows. The plant debris is pulled into the burrow where the soft parts are eaten with soil particles to grind the food. Another use for plant debris is to plug the burrow against moisture loss on hot days. Doing this, earthworms 'turn' the soil, getting nutrients from the surface down into the soil, making it available to microbes and plant roots. This also reduces layering in the soil. Earthworms can completely turn over the top six inches of soil every ten to twenty years.
You may be asking, since earthworms are so beneficial, can you just buy some? Yes and no. While you can buy worms for worm composting bins, they are not likely to survive in your soil. So you can't just buy them and add them to your lawn. You have to encourage the species of earthworms that are native to your soil by creating the ideal environment they need to thrive.
Because earthworms are important friends to an organically maintained lawn, and we can't just buy and add them to your lawn, we need to establish healthy turf conditions that they find inviting. Fortunately, following each of the Organic Lawncare Fundamentals presented in this educational series will create a turf ecosystem where earthworms can thrive. You should provide a cool, moist environment for your lawn's earthworms. This means shading soil from the sun by moving the grass at the high setting (see Step 3), and keeping grass thick by over-seeding bare and thin spots (Step 2). Compost provides organic matter that the earthworms will feed on (Step 7), and the same is true of leaving the grass clippings on the lawn (Step 2). The most important of the Organic Lawncare Fundamentals (Step 1), must not be overlooked. It is well known that pesticides are particularly toxic to bees, fish, birds, and aquatic life, and research has now confirmed that pesticides can devastate the earthworm population in a lawn. According to the University of Kentucky, even a single application of pesticides to your lawn (following the instructions on the bag), can kill 66% to 96% of your earthworm population. So go organic, keep the earthworms happy and your lawn will thank you.
- Pesticides and Earthworms: A Review
- Pesticides Make the Lives of Earthworms Miserable
- Toxicity of Pesticides to Earthworms in Kentucky bluegrass
- Ecological Golf Course Management by Paul Sachs
- Worm Mounds in Lawn Grass
- Garden's Homegrown Ally (Fungi)
- Importance of Organic Soil Life
- For an added boost, sprinkling a small amount of corn meal on the surface of the soil can promote rapid growth of your earthworm population
- Art of Vermiculture for Organic Gardening
Long Island Organic Landscapers
Although it's easy for the average homeowner to maintain their lawn organically, some may too busy and wish to hire a professional. In that case there are thousands of landscapers on Long Island to choose from, but only a small but growing number of experts who can maintain your lawn and landscape without the use of chemical pesticides. They can be found here.