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HOW TO MAINTAIN PESTICIDE-FREE LAWNS AND GARDENS
Aeration. You should aerate your lawn twice a year. Soil compaction is one of the largest causes of weeds. Aerating, or removing small cores or “plugs” of soil, allows air, water, and nutrients to reach the roots of the grass. Most lawns should be aerated. You can rent an aerator and share costs with your neighbors.
Aphids. Drench plants with strong sprays of water from a garden hose to kill aphids. (A hard, driving rainstorm will have the same effect), or you can spray aphids with a solution made from one part ordinary liquid dish soap and eight parts water. This is what we call a homemade botanical soap, but you can find ready-made kinds at a local garden center. Spray the stems and foliage of the infested plant with the spray, paying special attention to the undersides of leaves, since that is where aphids most commonly congregate.
Boiling water. Pouring boiling water over selected weeds can kill them. For even greater effectiveness you can use a flame weeder. Flame weeding machines use a targeted flame to kill weeds. Some examples of handheld flamers include Red Dragon (call 888.388.6724 to order) and Peaceful Valley Farm Supply sells several (888.784.1722).
Compaction. Compaction is an invitation for weeds. If your lawn is hard, compacted, and full of weeds, aerate to help air, water, and fertilizer to enter. If you can’t stick a screwdriver easily into your soil, it is too compacted. Get together with your neighbors and rent an aerator. Once you have an established, healthy lawn, worms and birds pecking at your soil will aerate it for free.
Crabgrass. Mix a couple of teaspoons of liquid dish soap in with water to get the water to stick to the crabgrass leaves. Spray the crabgrass with this solution then take some pantyhose and fill it with baking soda. Tap the pantyhose over the crabgrass to dust the leaves. It doesn't take much. It turns the leaves black within a day or two.
Dandelion. If untreated with pesticides, dandelions are edible and provide early nectar sources for bees. Plus, children love them! If you really can’t bear them, add calcium and lime; dig deep to get the whole root.
Disease. Disease problems are often the result of improper nutrient or moisture conditions. For example, dollar spot, a common lawn fungus, thrives on lawns with insufficient levels of nitrogen. The key to preventing lawn disease is to use locally adapted, resistant varieties of grass and follow sound cultural practices (proper mowing, watering, and fertilizing).
Fertilizer. Fertilizing in early fall ensures good growth and root development for your grass. Nitrogen, the most abundant nutrient in lawn fertilizers, promotes color and growth. Use a slow-release fertilizer formulation once a year, usually in the fall, to increase the efficiency of nutrient uptake and reduce nutrient runoff and leaching. Adding too much nitrogen, or quick-release synthetic fertilizers, can weaken the grass, alter the pH, promote disease, insect, and thatch build-up. Avoid synthetic chemical nitrogen-rich fertilizers that can kill valuable microorganisms in the soil and feed only the grass, not the soil.
Your grass clippings contain 58% of the nitrogen added from fertilizers, improve soil conditions, suppress disease, and reduce thatch and crabgrass. So, leave the clippings on your lawn. You can use a mulching mower and leave the leaves too. Plus, it’s free! Compost is an ideal soil conditioner, adding the much-needed organic content to your soil, and suppressing many turf pathogens. In the fall and spring, preferably after aerating, spread ¼ inch layer of organic or naturally-based compost over your lawn. Compost tea and worm castings are also great additions.
The best way to determine your lawn’s nutrient needs is by a soil test (see Soil pH and soil testing). As a general rule, however, use a natural/organic fertilizer with a balanced ratio of numbers close in proximity, such as 5-3-4. Watch for signals from your lawn. Learn to read the signals. For example, if clover is taking over the lawn, chances are the soil is lacking nitrogen since clover gets nitrogen from the air and grass gets nitrogen from the soil.
Look for compost or organic slow release fertilizers at your local nursery or order online. Some fertilizers, such as Ringer® Lawn Restore®, are certified by the Organic Materials Review Institute, Safer Brand. Other makers include North Country Organics; Harmony Farm; Peaceful Valley Farm Supply; and Down To Earth’s Bio-Turf.
Grass seed and seeding. Grass varieties differ enormously in their quality, resistance to certain pests, tolerance to climatic conditions, growth habit, and appearance. Some weeds are the result of using poor quality grass seed. While grass species vary across the country, most lawns are a mix of Kentucky bluegrass and fine fescue. Overseeding, or planting additional seeds in already established lawns, has been shown to reduce weed problems in some cases by creating a dense turf that out-competes weeds. Site conditions (sun or shade) vary, but good choices for cooler regions are combinations of Kentucky bluegrass, Perennial ryegrass, fescues, Fairway wheatgrass, and Bent grass. Adding clover to the seed builds in a source of nitrogen. A mix of two or more grass varieties is preferable.
Insects. Your control strategy will depend on your particular pest problem. You can control grubs over time by applying the bacterium Bacillus papillae (milky spore disease), which, once established, will provide control for decades. Grubs can also be combated by spraying the infected areas with organic nematodes and a fungus that infects the grubs. After the spray is applied, water the lawn, and then aerate about a week or so later. Kill chinch bugs by drenching the thatch layer with an insecticidal soap. Sod webworms can be controlled by de-thatching and applying Bacillus thuringiensis (Bt) when larvae are present, applying nematode parasites, or with insecticidal soap. Although considered least toxic, insecticidal soap is toxic to most insects when they are drenched with it, and Bt is toxic to caterpillars.
Mowing height. Bad mowing practices cause many lawn problems. Mowing lower than 1 ½ to 1 ¾ inches can kill the root system by preventing photosynthesis, and mowing with a dull blade makes the turf susceptible to disease. A low mowing height also invites sunlight in for weeds to sprout. Generally, you should keep a lawn at 3- 3 ½ inches. Mowing high allows the grass to develop deeper, drought-resistant roots systems. For the first and last cut of the season, mow to 2 inches. Do not mow more than 1/3 of the grass blade at a time. Keep your mower blades sharp to prevent the development and spread of fungal disease, or ask your service provider to sharpen their blades frequently. Leave clippings on the lawn (this is free fertilizer), but rake it slightly to break up clumps. Rotate the mowing pattern to reduce lawn compaction. Mow frequently enough to ensure that weeds are unable to build up energy reserves and become well established. Weeds can also be pulled by hand. If you feel that an herbicide is necessary, corn gluten is an excellent pre-emergent, and a fatty-acid soap product called Sharpshooter™ is an effective broad-spectrum herbicide.
Pest control. Any control strategy will depend on the type of problem. A zero-tolerance for bugs or weeds can backfire since in small numbers they can be beneficial to the lawn and ecosystem. Infestations indicate the lawn is in stress. Always identify the problem before treating it. See Natural solutions to pest control and Insects.
pH. Test your soil and adjust the pH if necessary. Low pH means high acid content—add lime to raise the pH and lower the acidity. High pH means high alkaline—add sulphur to lower the pH, taking care not to add too much and burn the lawn. Watch for hints of pH imbalance such as dandelion infestation. Dandelions love soil with a 7.5 pH, while most grass varieties prefer a pH of 6.7-7.0. Nothing will successfully conquer a dandelion problem without correction of the lawn’s pH. A soil test through the University of Connecticut costs $8.00 and should be done before you do anything at all to your lawn. This link takes you to the University of Connecticut's soil test form and questionnaire.
Poison ivy. The only accepted organic method is to manually pull it out, it will grow back unless you hoe out the roots, but the key is to go back and pull it out again and again, until the root's energy reserves are tapped. Use large plastic bags around your arms, then after you pull the plants, turn the bag inside out, or duct tape your gloves to your shirt sleeves. Apply Tea Tree Oil to your skin if you get the rash. If you can borrow a goat, they love to eat the stuff! A word of caution, never ever burn it. This can be fatal.
Soil pH and soil testing. If you top-dress with compost, water, and mow your lawn properly, you should see acceptable results. However, if you want a more manicured look, get your soil professionally tested. Soil tests are available from the Cooperative Extension Service of state universities and private soil labs. (The over-the-counter tests you find at hardware stores and garden centers aren’t worth it.) A soil test through the University of Connecticut costs $8.00 and should be done before you do anything at all to your lawn. This link takes you to the University of Connecticut's soil test form and questionnaire. For information call UCONN’s soil analysis laboratory at 860-486-4274, email email@example.com. Test results will come back to you in the form of a computer printout with detailed information about the condition of your soil, as well as what to do about it. Low pH means acidic conditions and high pH indicates alkaline conditions. If the pH is too high, your grass cannot properly absorb nutrients. Ideal pH should be between 6.5-7.0, slightly acidic. Generally, lime is added to raise the pH and sulfur is added to lower the pH, and adding compost can naturally correct your pH.
Soil probe. Sample the soil with a “soil probe”—cut or dig a small hole about 10” deep with one side that is straight and smooth. The lawn should have between 5”-6” of topsoil, which is the darkest soil layer. If needed, add topdressings of organic matter, such as composted manures (they do not have an odor), to the topsoil.
Strawberry (wild). Small wild strawberry infestations can be mechanically controlled by hand-pulling or digging out the entire plant from the soil. Corn gluten meal is an organic weed preventer that can discourage sprouting of new wild strawberries. Ordinary white vinegar (combined with a little liquid dish soap to help it adhere) can at least burn the top growth of wild strawberries, but be careful, because it will also burn the grass. No matter what you use, whether chemical or organic, there's a good chance the strawberries will regrow. Your best defense against this persistent weed is to aerate your lawn and overseed with a combination of appropriate grass seeds at least once annually. Some people even use flame weeders, which are propane torches that burn weeds. But again, they'll take out the grass along with the weeds.
Thatch. Thatch is a dense layer of grass stems and roots on the surface of the soil. Thatch is a symptom of shallow watering and chemical fertilizer usage. When thatch layers become ½” or more, the roots will grow up within the thatch instead of in the soil, making grass susceptible to insects, disease, and weather stress. If your lawn feels spongy, you may have thatch buildup. Thatch is reduced by aeration, topdressing with organic matter, or power raking/vertical mowing, which requires special equipment and will result in temporary aesthetic damage to the lawn. In healthy lawns, earthworms and soil microorganisms break down the thatch.
Ticks (Lyme disease). Organic tick spraying is effective and widely available. Chemical solutions are synthesized from the sources used in organic, namely chrysanthemum oil, garlic and cedar oil among others. See our list of land care providers for an organic tick control applicator. It is also highly recommended to focus on prevention. See our brochure on Lyme disease prevention for tips and techniques.
Vinegar, horticultural or acetic acid. This is effective at killing certain weeds. Avoid spraying other green vegetation, such as turfgrass, since this is a nonselective plant killer. Use with caution, since concentrations of acetic acid greater than 5% can cause skin irritation or eye damage. Even regular white vinegar (5% acidity) can do the trick, especially on walkways, patios, and cracks between paving.
Watering and poor drainage. Drought conditions, excessive watering, or poor drainage due to soil type are all invitations for weeds. Watering needs are very site specific, but generally speaking, a deep watering of about one-inch once a week in the early morning is best. Avoid frequent, shallow watering, which promote shallow root systems and reduce stress resistance. Natural, organic fertilizers can increase the water-holding capacity of the soil. Your type of soil affects your drainage and is also site specific. Once you establish a deep root system from mowing high, you will need less water. Check with your local nursery for more specific recommendations and your soil type.
Weed identification guide. Click on this link for a photographic weed identification guide from Better Homes and Gardens. Note that in all cases they recommend either a pre-emergence herbicide or a post-emergence herbicide to control the weed. In organic landcare an example of a pre-emergence herbicide might be corn gluten, an example of a post-emergence herbicide might be vinegar or an OMRI-certified product called Burnout. This is merely to point out that while the market is flooded with toxic products, non-toxic or healthier options do exist. Weed Identification Guide.
White clover. Clover is cool! It takes nitrogen from the atmosphere to feed it to the soil, and is a source of nectar for bees. If you really don’t want to let it grow, add nitrogen, lime, and compost.
Dec-Feb: Don’t park or walk excessively on lawn.
March: Rake up leaves and debris.
May: Top-dress with compost or organic fertilizer.
June: Begin watering as needed.
July: Monitor irrigation.
Late August: Top-dress with compost or organic fertilizer.
September: Limit watering.
October: Begin fall cleanup.
November: Remove all leaves and debris.
Dec-Feb: Don’t park or walk excessively on lawn. Use calcium chloride and/or sand for snow instead of rock salt (sodium chloride), which is toxic to plants and pets.
March: Rake up leaves and debris.
April: Apply compost tea. Pull weeds by hand or spot-spray as needed with organic herbicide.
May: Dethatch and aerate as needed. Apply calcium-rich fertilizer and other amendments as per soil test. Top-dress with compost or organic fertilizer.
June: Stay vigilant with weeds. Begin watering. Apply compost tea.
July: Monitor irrigation. Monitor insects.
Late August: Top-dress with compost or organic fertilizer. Evaluate and pull/dig summer weeds. Monitor irrigation. Overseed with appropriate grass seed.
September: Limit watering.
October: Begin fall cleanup.
November: Remove all leaves and debris. Apply compost tea.
Dec-Feb: Don’t park or walk excessively on lawn. Use calcium chloride and/or sand for snow instead of rock salt (sodium chloride), which is toxic to plants and pets. Stake where pavement ends and lawn begins so that snow plow knows where to go.
March: Rake up leaves and debris. Begin regular mowing with blade low.
April: Apply compost tea. Pull weeds by hand or spot-spray as needed with organic herbicide. Apply corn gluten when forsythias bloom.
May: Dethatch and aerate as needed. Apply calcium-rich fertilizer and other amendments as per soil test. Top-dress with compost or organic fertilizer. Consider first overseeding or wait till late August. Apply beneficial nematodes for grub control.
June: Stay vigilant with weeds. Begin watering. Apply compost tea. Monitor billbug, chinch bug, sod webworm, and other insect pests.
July: Monitor irrigation. Monitor insects.
Late August: Top-dress with compost or organic fertilizer. Evaluate and pull/dig summer weeds. Monitor irrigation. Overseed with appropriate grass seed. Apply compost tea. Dethatch and aerate as needed. Apply calcium-rich fertilizer.
September: Limit watering. Apply beneficial nematodes as needed.
October: Begin fall cleanup.
November: Remove all leaves and debris. Apply compost tea. Mow low without scalping.
A microbe-rich brew made with high-quality compost can be sprayed on lawns to replenish and reactivate the biology in the soil. Compost tea doesn’t have a long shelf life so it must be applied when fresh. To find professionals who can brew and apply compost tea for you, visit organiclandcare.net. Home brewers are available for do-it-yourselfers.
Grub Control with Beneficial Nematodes
Healthy lawn soil hosts dozens of nematode species that keep grubs under control. While soil biology is being restored with compost, compost tea, and proper mowing practices, Beneficial Nematodes can be used to control grubs. North Country Organics is one source, product name “Grub Guard”, available at www.norganics.com.
Spot Treatment for Driveways, etc. (safe alternatives to Roundup)
Burnout, available at www.norganics.com
Nature’s Avenger, available at www.naturesavenger.com
White vinegar 5% acidity, available at your local supermarket
SafeLawns founder, author, and filmmaker Paul Tukey
hosts award-winning visual guides to lawn care. This extensive video
library includes such topics as controlling weeds, proper mowing and
watering, sod, and compost.
Photo copyright by Stanislav Duben