Eliminate the Conditions that Promote Weeds

• 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!


• 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.While grass species vary across the country, most lawns are a mix of kentucky bluegrass and fine fescue. 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.


• Soil pH and Soil Testing – 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. Thriving dandelions indicate a pH of about 7.5.Generally, lime is added to raise the pH and sulfur is added to lower the pH, and adding compost can naturally correct your pH. A soil test is highly recommended to determine the soil pH and specific nutrient needs. Contact your extension service to find out how to take a soil sample. In addition to nutrients and pH analysis, ask for organic content analysis, and request organic care recommendations. Organic content should be 5% or higher.


• Fertility - Soil testing is the best way to determine your soil’s specific nutrient needs. 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. Adding too much nitrogen, or quick-release synthetic fertilizers, can weaken the grass, alter the pH, promote disease, insect, and thatch build-up. 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.

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. 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, http://www.saferbrand.com/. Other makers include North Country Organics, http://www.norganics.com/; Harmony Farm http://www.harmonyfarm.com/; Peaceful Valley Farm Supply, http://www.groworganic.com/

Read Your Weeds

Weeds can tell you a lot about the condition of your lawn and indicate what you need to do to grow healthy grass that is naturally resistant to weeds and pest problems. Learn to read your "weeds" for what they indicate about your lawn care practices and soil conditions, and you’ll be on your way to creating a healthy lawn that will be less work in the long run.

Reading weeds is actually very simple. First, know that weeds thrive in soil that is compacted, poorly fertilized, and not pH balanced; and in lawns that are improperly watered, seeded, and mowed.

Synthetic fertilizers and chemical pesticides also lead to undesirable conditions, which restricts water and air movement in the soil. High nitrogen fertilizers can disrupt the nutrient balance, accelerate turf growth, increase the need for mowing and contribute to thatch buildup. Pesticides harm the microorganisms, beneficial insects and earthworms that are essential to maintaining healthy soil, and therefore, healthy turf.

For instance, blue violets often indicate compaction and excessive watering. Aeration and proper irrigation would correct the conditions that are promoting blue violet growth.

Remember, many plants that are considered weeds, have beneficial qualities. Try to develop a tolerance for some weeds. For instance, clover - considered a typical turf weed - thrives in soil with low nitrogen levels, compaction issues, and drought stress. However, clover takes free nitrogen from the atmosphere and distributes it to the grass, which helps it grow. Clover roots are extensive and extremely drought resistant, providing significant resources to soil organisms, and clover will stay green long after turf goes naturally dormant. Crabgrass provides erosion control, dandelions’ deep roots return nutrients to the surface, and plantains are edible!


source: Read Your "Weeds", A National Coalition for Pesticide-Free Lawns Factsheet – http://www.pesticidefreelawns.org/ .

Caring for your Lawn Organically

• Improve the Soil: The first step is to test the soil's pH - it should read between 6.5 and 7.0, which is slightly acidic. Soil that is too acidic will need a sprinkling of lime; sulfur can be added to soil which is not acidic enough. You can buy a pH tester (see below, this page) for $40 - $60. Another solution is to have your soil tested professionally; first call your extension office - they often provide soil testing as a free service. Lawns grow best in loamy soils that have a mix of clay, silt and sand. Too much clay in the soil mix, or heavy use, can compact the soil and prevent air and nutrient flow. Compacted soil may need aeration, a process of lifting small plugs of turf to create air spaces in the soil. For best results, rent an aerator or hire a lawn service to do the job - this will remove "finger size" plugs which improves aeration. Aeration is best done before top dressing and fertilizing. Organic matter, such as compost and grass clippings, will benefit any type of soil; it lightens soil which is heavy in clay, and it builds humus in sandy soils, which helps retain water and nutrients.



• Choose a Locally Adapted Grass: Grasses vary in the type of climate they prefer, the amount of water and nutrients required, shade tolerance and the degree of wear they can withstand. Ask your local garden center to recommend grass which is best adapted to your area.
  


• Mow Often, but Not Too Short: Giving your lawn a "Marine cut" is not doing it a favor. Surface roots become exposed, the soil dries out faster and surface aeration is reduced. As a general rule, don't cut off more than one-third of the grass at any one time. Most turf grass species are healthiest when kept between 1.5 and 3.5" tall depending on species of turf.
  


• Water Deeply but Not Too Often: Thorough watering encourages your lawn to develop deep root systems which make the lawn hardier and more drought-resistant. Let the lawn dry out before re-watering; as a rule of thumb, the color should dull and footprints should stay compressed for more than a few seconds. When watering, put a cup in the sprinkler zone; it should get at least one inch (2.5cm) water.The best time for watering is early morning - less water will be lost to evaporation. Ideally, it's better to water the first half-inch or so, then wait for an hour or two before watering the second half-inch.
  


• Control Thatch Build-Up: Thatch is the accumulation of above-soil runners, propagated by the grass. This layer should be about 1/2" ( 1.25cm) on a healthy lawn, and kept in balance by natural decomposition, earthworms and microorganisms. Too much thatch prevents water and nutrients from reaching the grass roots. You can reduce thatch with a steel rake, or by renting a de-thatcher or aerating the turf once per year.
  Watering needs for different grass types:
  

How long can you wait between waterings before the lawn starts to go brown?

12 - 21 days: Bahia grass, Buffalo grass, Bermuda grass, St. Augustine grass, Centipede grass
8 - 12 days: Carpet grass, Fine fescue, Kikuyu grass, Seashore paspalum, Tall fescue, Zoysia 5 - 7 days: Ryegrass, Kentucky bluegrass, Bentgrass

The fine-leaved fescues (grass blades) as well as the "common" types of Kentucky bluegrasses, such as Park and Kenblue, require less water, fertilizer and cutting than turf-type perennial ryegrass or many of the newer "improved" types of Kentucky bluegrass.

Source: University of Georgia, College of Agricultural and Environmental Sciences