Healthy lawns grow on healthy soil. These practices, recommended by turf professionals, will help build fertile soil and vigorous deep-rooted lawns. Healthy lawns can resist disease and drought damage and out-compete most weeds, without reliance on chemicals. Scientific studies have shown that many commonly used lawn chemicals (such as pesticides, quick-release fertilizers, and “weed-and-feed” products) can kill beneficial soil organisms and contribute to soil compaction, thatch buildup, and lawn diseases. They may also harm human health, pets and wildlife, and contaminate streams and lakes. For a healthy, attractive lawn that’s easy to care for, follow these proven practices:
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1) Mow Higher, Mow Often, and Leave the Clippings
2) Fertilize Lightly in The Fall With A “Natural-Organic” or “Slow-Release” Fertilizer
3) Water Deeply, To Moisten The Root Zone, But Infrequently
4) Improve Old Lawns With Aeration, Overseeding, And Top Dressing With Compost
5) Avoid Using Pesticides, Quick-Release Fertilizers, And “Weed-And-Feed”
6) Consider Alternatives To Grass For Steep Slopes Or Shady Areas
Set mowing heights at 2 1/2 to 3 inches for most lawns. Mow when the grass gets 50% taller than the desired height. Mow regularly, even on summer-dormant lawns, to keep weeds from setting seed.
Leave the clippings on the lawn: “Grasscycling” provides free fertilizer, helps lawns grow greener and denser, and doesn’t cause thatch buildup. (Thatch is last year’s woody roots and stems, not clippings.) Mow when the grass is dry and keep mower blades sharp for best results.
When it’s time to buy a new mower, consider a “mulching” mower. They chop clippings finely and blow them down into the lawn so they disappear.
Natural fertilizers release nutrients slowly through the year, won’t leach away, and support the variety of soil organisms that improve fertility and combat diseases. Healthy lawns are a lighter “meadow” green color. Deep blue-green lawns are over-fertilized and unhealthy: more prone to disease and thatch buildup and drought damage. Fertilize lightly!
Fertilize in the fall to build the grass plant’s nutrient reserves. Never fertilize in early spring because that makes grass grow too fast and robs its reserves. Late spring and early fall are O.K. to fertilize too, but late fall is the single best time. Remember, grasscycling returns valuable nutrients to the soil every time you mow! Add lime in the fall or spring, if a soil test shows a calcium deficiency or acid soil.
Grasses do best when the whole root zone is wetted, and then dries out between waterings. Avoid frequent shallow watering that causes poor root development. Over-watering also promotes lawn disease.
Aerate (or dethatch) if water won’t penetrate the surface because of soil compaction, steep slopes, or thatch buildup.
Water about one inch per week in mid-summer. Water slowly, or start and stop, so the water penetrates rather than puddling and running off. Don’t water in the heat of the day, that promotes disease and wastes water.
Consider letting the lawn go brown and dormant in the summer. Watering deeply (but slowly, so it penetrates) once each rainless month will help dormant lawns to recover better in the fall. Avoid heavy traffic that can damage dormant lawns, or water just the play/high-use areas to prevent damage.
Aerate in spring or fall. Use a rented power-aerator for best results. Or insert a garden fork 6″ deep every four inches and lever back to loosen the soil.
Overseed, after raking or aerating to expose soil, with a rye/fescue mix designed for Pacific Northwest conditions talk to a knowledgeable nursery-person or call WSU Cooperative Extension (296-3900) for seed recommendations.
Top dress with fine compost (screened to 3/8 -inch) one-quarter inch deep, raked out so the grass stands up through it. May or mid-September are the best times for aerating, over-seeding, and top dressing.
Dethatch in early spring if thatch accumulations over 1/2 -inch thick, or decompose thatch slowly by aerating and top dressing. Overseed after dethatching, to keep weeds out. Reduce fertilizer levels and over-watering, and aerate if needed, to avoid future thatch buildup.
These products can damage soil and lawn health, and pollute our waterways. Pesticides and “weed-and-feed” may also harm people, pets, and wildlife. Accept a few “weeds,” particularly clover that improves the soil. Target the ugly weeds, leave the others.
Remove weeds by hand in spring and fall (pincer-type weed pullers work great in moist soil), or spot-spray problem weeds (read and follow herbicide label warnings).
Crowd out weeds by growing a dense lawn. Mow higher, leave the clippings, fertilize properly, and improve thin areas with aeration, overseeding and top dressing.
Grass grows best in well-drained soil on level or gently sloping areas, in full sun. Call WSU Cooperative Extension (296-3900) for information on alternative plants that do well on shady, steep or wet sites.
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