Weeds, Beetles, and Diseases
Do you have lawn problems that need a cure? Walt Whitman called weeds “plants whose virtues have yet to be discovered.” Lawn owners would surely agree with him!
Many lawn owners want opposing things—the perfect lawn and no chemicals. The key to a chemical-free lawn is patience. Soil that's been chemically treated has lost its naturally occurring, beneficial micro-organisms that nourish healthy plants. Like any addict, it will suffer withdrawal symptoms—in the case of a lawn, slow or patchy growth.
If you don't want to use chemicals on your lawn, the best defense is a good offense. A thin layer of compost, manure, or other organic material forestalls the common weeds, bugs, and diseases. When problems do arise in the lawn, the are many natural alternatives to using herbicides, pesticides, and fertilizers. Along the way to becoming chemical-free, you may even find a virtue or two in some common weeds.
Crabgrass, the weed everyone loves to hate, tops America's list of lawn complaints. The best crabgrass preventer is a healthy, thick lawn and soil with the proper pH balance (7.0-7.5). Perennial rye grass is the best competition for crabgrass. It also provides some insect control, as it emits a natural poison that gives some small, damaging bugs the “flu.”
Fertilizing is key and must be done in the spring and in the fall. Crabgrass thrives in compacted lawns. Aeration can help. A mixture of 1 pint of hydrogen peroxide, diluted to 3 percent, per 100 square feet of lawn can help eradicate the pesky plant.
Corn gluten meal, a relatively new and increasingly popular natural herbicide, appears to be successful at preventing crabgrass and other common weeds. A by-product of milling corn, it is completely benign. A three-year systematic application can yield a nearly weed-free lawn. Research at Iowa State University showed that 60 percent of weeds are eliminated the first year, 80 percent the second, and 90 to 100 percent the third year of corn gluten meal application. Some companies sell a pelletized form containing potash and nitrogen, but you may have to search a bit or ask your retailers to stock it. (Gardens Alive! sells W.O.W. [Without Weeds] in a 50-pound bag, enough to treat a 2,500-square-foot lawn the first year. Call 812-537-8650 for details.)
Your neighbors probably wouldn't stand for a dandelion yard, but consider this: Dandelions make great wine, are a natural diuretic, can be dried and made into coffee, and can be braided into lovely necklaces. You can eat their young leaves in salads, and in fact, they were brought to this land as an exotic green. They're an excellent source of potassium, phosphorus, calcium, and vitamin A.
Not convinced and still want to get rid of your dandelions? Get a weeding fork. Dandelions have a two-year life cycle. When they're in the first year and appear as basal foliage, dig them out with a vengeance. It's great exercise. If you miss some and they flower the next year, dig them out before they reach the seed (white puffy) stage. If you let them go to seed and spread their progeny, you'll have to start the process all over again.
A thick, healthy lawn is again the best defense against dandelions, as it is for other common broadleaf weeds such as creeping charlie (jenny) and quack grass.
Insecticides or pesticides are hardly ever necessary to control the most common lawn pests. Japanese beetle grubs and their adult counterparts are a problem in much of the eastern United States. They cause lawns to turn yellow and die but are fairly easily controlled through nonpoisonous means. In the grub stage of late spring and fall (beetles have two life cycles per season), spray the lawn with 2 tablespoons of liquid dishwashing soap diluted in 1 gallon of water per 1,000 square feet. The grubs will surface and the birds will love you. Spray once each week until no more grubs surface. In the adult beetle stage, handpick them and squish them, or drop them into a bucket of soapy water.
Two biological controls for Japanese beetles are beneficial nematodes and milky spore disease. These will not harm people or pets. Milky spore disease is a bacterium that controls chewing insects, including beetles, and can be purchased under several brand names. Once established in your soil, it lasts up to 20 years as an effective beetle control. Buy it at your local garden center, follow the directions to the letter, and apply in late spring or fall.
Chinch bugs are annoying creatures that smell bad when you crush them and make yellow or brown patches in your lawn, especially in dry conditions. Watering well for 3 to 4 weeks can keep them under control. Or soak the sod with a solution of 1 ounce of dish soap and 2 gallons of water, and cover the grass with a flannel sheet to catch the bugs as they flee. Experts agree that insecticides and human control have nearly the same efficacy against chinch bugs.
A spongy lawn indicates a thatch problem. This tightly intermingled layer of dead and decaying vegetation—an unhealthy build-up of organic matter that can cause brown patches in a lawn—indicates a pH imbalance. Thatch is a problem especially in lawns previously treated with chemicals where the grass's natural ability to decay has been destroyed. Dry thatch repels water, while wet thatch invites fungal diseases.
The best control is raising the lawn soil's pH level. One way to do this is to rent a power rake (inquire at your garden supply center), which uses rigid wire tines or steel blades that slice through the thatch and lift the debris and some soil to the surface to encourage natural decay. The best time to de-thatch is in late spring. Don't do it during midsummer, when the lawn may be stressed, or when the lawn is wet. Hand raking is less harsh but can be impractical and back-breaking work for large lawns. Molasses diluted with hot water and sprayed on the lawn can help stimulate natural organisms to eat the thatch layer.
Aeration also helps. Healthy soil should be 50% solid, 25% water, and 25% air. To achieve this ideal, improve overall lawn health, and help prevent fungal diseases, you can rent “plug” machines that take out chunks of soil and redeposit them on your lawn. Some catalogs sell aerating sandals with long spiked soles. Gardeners are meant to strap these scary-looking things to their feet and walk around on the lawn. Users claim, however, that they take far too much weight and leg strength to be effective.
You can manually aerate your lawn with a spading fork; experts recommend about one hole per every few inches of lawn. Get to work in the spring or whenever compacting and thatch seem to be a problem.
To obtain a free brochure on natural lawn care, contact American PIE, 124 High St., Box 340, Glastonbury, CT 06073-0340; 800-320-APIE (2743); www.americanpie.org.
Four Steps to a Healthier Lawn
- Test your soil: The pH balance should be 7.0 or more—6.2 to 6.7 puts your lawn at risk of fungal diseases. If the pH is too low, correct it with liming, best done in the fall.
- Mow only when the grass is at least three inches tall. This encourages deep roots. Leave grass clippings on the lawn as a natural fertilizer.
- Don't over-water. Make the lawn seek its own source of water, building longer and sturdier roots. Cut back on water especially in midsummer to let the lawn go dormant, strengthening it for fall and winter.
- Control the weeds by promoting healthy lawn growth with natural fertilizers in spring and early fall.