Sunday, April 6, 2008

Natural Lawn Care

by Erica Kempter from Nature and Nurture, LLC
originally appeared in the summer 2006 Project Grow Newsletter
photo by
Selva Morales under Creative Commons License

The goal of natural turf maintenance is to develop and maintain healthy lawn ecosystems. Different organisms occupy varying ecological niches. By keeping most of the niches “filled” with desired organisms, the delicate balance of nature favors a healthy lawn. Disruption of this balance can lead to lawn problems. One type of disruption is the creation of “empty” niches. For example, bare soil is an “empty niche” that invites weeds to enter the lawn. Another example is that of beneficial fungi in the soil. Over 400 species of fungi are known to live in the soil and thatch of lawn. Of these, less then 25% are potentially harmful (Daar; 1992). That means that over 75% of these fungi are occupying a niche that could otherwise by filled by bad fungi. That’s why even one application of lawn pesticides can be harmful to the lawn because it
indiscriminately kills fungi, throwing off the natural fungal balance leaving the lawn wide open for attack. For example, an herbicide is used to kill weeds, lowering the fungi population and creating empty niches. Something as simple as an unusually wet period combined with pest fungi that were previously kept under control by beneficial fungi now have their opportunity to attack the lawn. This can cause significant visual lawn damage. So to control the fungus, a fungicide is applied to the lawn. The additional pesticides make the lawn even more susceptible to problems creating a cycle where the lawn becomes more and more dependent or “addicted” to chemicals for control and prevention of pests and disease. This is what is often called the
chemical treadmill.

Fortunately, due to nature’s incredible ability for regeneration, even the most problem stricken, chemically dependent lawn can recover. The most important thing that you can do for your lawn is to increase the organic matter content of the soil. Organic matter improves drainage, water holding capacity, nutrient holding capacity, encourages earthworms, counters soil compaction and provides food for microorganisms that feed the grass. This is the foundation of a healthy lawn ecosystem. Organic matter can be added as lawn clippings, compost, decomposed manures, and some fertilizers that are high in organic matter. Here are 10 Tips for a healthy lawn:

  1. Mow high. Set lawn mower to 2-3” high. Helps prevent weeds, drought, and grubs.
  2. Mow with sharp mower blades. Sharpen the blades at least once per year. Shredded grass blades are more susceptible to disease.
  3. Mow when dry. Ideally, mow when the soil is dry on the surface. Mowing wet soil can spread disease and using heavy equipment on wet soil compacts the soil causing poor drainage and other problems.
  4. Leave clippings on lawn. They will break down to provide natural fertilizer and organic matter to the lawn.
  5. Water deeply and occasionally. Instead of shallow and often. During droughts, for most lawns (depends on soil type and irrigation type) water 1x–2x per week for 45-60 minutes. This prevents damage to lawn from lack of water, discourages disease by allowing soil surface to dry, and encourages deep root growth.
  6. Fertilize. Apply compost or an organic-based fertilizer 1-2 times per year. This provides essential nutrients and organic matter.
  7. Monitor lawn. Keep an eye out for problems so they can be dealt with before getting out of control. Look for unusually colored patches, mole runs, thin grass, bare soil, and dug up areas. Along with these, a lawn monitoring program includes checking the soil for grub populations and soil compaction.
  8. Weed control. Hand remove weeds. Try the “water weeder” sold by Lee Valley Tools for dandelions and other tap rooted weeds.
  9. Grub control. White grub infestations can be treated with beneficial nematodes. It is best to apply them in the fall. Nematodes have a short shelf life and die in dry soil so follow instructions precisely and only order if planning to apply them soon.
  10. Got a headache? If all of this sounds like a headache, consider reducing your lawn and replacing it with low maintenance native prairie or woodland plants, sedges, moss, or edible plants. The possibilities are endless!

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