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by Michael Schmahl

Today’s society dictates that we must all have perfect teeth, the perfect body and a perfect lawn. However, not everyone subscribes to this ideology. A growing number of homeowners and businesses are interested in organic lawn care. With the addition of a child or pet, families often start asking more questions about the products being used on their lawn. Similarly, leading corporations are adopting "green" practices such as sustainable development and environmental stewardship. Whatever the motivation or reason may be, organic lawn care is a viable alternative to conventional spray programs.;

To begin with, lawns should be carefully planned and designed prior to their establishment. Lawns are not unlike any other perennial planting. It is quite common for a homeowner to invest time learning about the cultural requirements of trees and shrubs prior to making a purchase, yet a lawn is usually denied this process. All too often, during the construction phase of residential subdivisions or commercial developments, topsoil is stripped as heavy equipment drives through followed by the low-bidding contractor rolling out sod. No wonder modern day lawns develop a host of problems and require medication in order to survive.

When it comes to lawn establishment, an ounce of prevention is worth a pound of cure. A thorough assessment of existing site conditions will indicate such factors as exposure, topography, air circulation and competition with other landscape components. This evaluation will ultimately determine the suitability of turf and the appropriate selection of grass varieties. Utilizing other groundcovers to minimize lawn areas is one way to reduce maintenance requirements as well as the high inputs that turf requires. Consideration should be given to other plant materials that offer ornamental features such as flowers, berries and evergreen foliage. For example, Pachysandra terminalis and Vinca minor are a better choice than grass in shady locations.

Organic lawn care doesn’t mean just saying "NO" to chemicals. It is a complete management program that includes proper watering and mowing, overseeding/grass selection, core aerating and organic fertilizing. The real key to chemical-free gardening is good horticultural practices, while placing an emphasis on building and sustaining healthy soil.

"A healthy soil grows healthy plants" is the fundamental principle of the organic approach. Soil is often the most neglected component of the turf ecosystem, since the color of green is usually the quality standard by which lawns are judged. Lawns are dependent on the soil to provide a nutritionally balanced environment from which to grow. A healthy soil is supported by a tremendous variety of beneficial microorganisms such as bacteria and fungi. Although these tiny workhorses can’t be seen with the naked eye, we greatly benefit from their activity and know that they are there. In the compost heap, the heat given off is a by-product of microbial activity. Microbes enhance the soil-building process by decomposing organic matter and creating humus. Humus is the dark, stable material that is the "glue" that holds soil aggregates; it provides excellent nutrient retention, ideal drainage and good soil structure.

Organic fertilizers stimulate soil microbes by providing a constant supply of organic matter. As a result, these fertilizers feed the grass plant as well as the soil. Organic fertilizers generally require less energy in their manufacture when compared to their conventional counterparts and at the same time, reuse and recycle materials. For example, North Country Organics of Bradford, Vermont manufactures fertilizers that utilize cocoa meal, a waste product from the Hershey chocolate factory in Pennsylvania. Cocoa meal not only adds a pleasant aroma to the fertilizer, it is high in nitrogen. Other fertilizer ingredients include Chilean nitrate (natural nitrate of soda) as a nitrogen source, black rock phosphate for phosphorus and New Jersey greensand (glauconite), a naturally occurring silicate, as a source of potassium, iron, calcium and magnesium plus over 30 trace minerals. A wide range of slow-release natural organic products is commercially available today. Synthetic fertilizers are typically made slow-release by the addition of a sulphur coating, whereas organic fertilizers are slow-release simply because naturally derived materials break down gradually and continuously, much like Mother Nature herself.

Mowing is the most commonly practiced lawn care operation. For the home lawn, an environmentally friendly rule of thumb is to simply mow high. A taller mowing height accomplishes several important functions. Since roots grow in proportion to top growth, a lawn maintained at a height of three inches will have a deeper root system than that of a closely clipped turf. This deep, dense root system will require more grubs per square foot to show signs of damage than the short-cropped lawn. Just raising the height of cut increases the lawn’s threshold level for grub attack. Also, taller grasses have more leaf blade surface area which maximizes photosynthesis and produces a healthier plant. Tall grass will shade the soil surface and consequently reduce weed seed germination. Research has proven that a one-inch increase in mowing height results in a 10 per cent reduction in weed populations.

Many municipalities today (I would hope all municipalities by now) do not accept grass clippings or garden debris. These materials are completely recyclable and have no business in a landfill. Grass clippings represent free fertilizer and should be left on the lawn. However, through life’s many demands, the lawn may not always be cut on time. Clippings that are excessive and physically block sunlight from reaching the turf should be raked up and, ideally, composted. Mulching mowers are designed to cut grass into very fine clippings and effectively incorporate them back into the turf. Over the course of a full growing season, grass clippings can be the equivalent of one fertilizer application.

The apparently simple task of watering is frequently performed incorrectly. The guiding principle governing the frequency of watering is to water deeply and infrequently. The soil should be allowed to dry out through much of the depth of the root zone. This dry-down is a workout for the grass plant which stimulates deeper root penetration. As roots search for moisture, their system expands into a dense network that increases drought resistance while enabling the grass plant to lap into a broader nutrient base. It’s time to water when the first symptoms of wilt appear. When Kentucky bluegrass wilts, it takes on a darker color as leaf blades fold inward in an attempt to conserve moisture and reduce desiccation.

Early morning is the best time to water the lawn. Winds are usually calmer in the morning hours and temperatures cooler. Early morning watering represents a form of disease prevention. Spores to a fungus are like seeds to a plant – both require nutrients and moisture in order to grow. This is precisely what dew represents for developing diseases. Morning waterings rinse dew off the leaf blades, helping to discourage disease. Watering during the heat of the day is wasteful because of losses from evaporation. Watering late in the day or in the evening can promote disease incidence since many pathogens require an excess of six hours of leaf blade wetness in order to set up.

When it comes to lawn weeds, beauty truly is in the eye of the beholder. Weeds are generally herbs or wildflowers and many have healing or medicinal qualities which have benefited mankind throughout the ages. It is important to realize that even under ideal conditions some weeds will grow. A weed is simply a misplaced plant and represents nature’s way of covering and protecting soil from erosion.

Weeds are an indication of soil or maintenance problems and not the problems themselves. Natural weed control addresses the true cause of the concern rather than merely treating the symptom. Crabgrass is a weed that is best prevented by good horticultural practices and by understanding its life cycle. Crabgrass is an annual and sets seed in the fall. The following season, these seeds need light in order to germinate. Given these two facts, a preventive maintenance plan is the best control strategy. Renovating or overseeding during the fall, when crabgrass plants are declining, will thicken the lawn and give it the competitive advantage. Maintaining a tall mowing height during the following growing season will reduce the amount of sunlight reaching the awaiting seed. Spraying for crabgrass may provide temporary relief, but if no attempt is made to correct the underlying conditions that favor this weed, it will return.

Healthy lawns are more resilient and resistant to attack by pests and disease and will tolerate some degree of insect damage. Endophytes are types of beneficial fungi that live within the grass plant. Unlike disease-causing fungi, endophytes do not cause any harm to turfgrasses. They benefit lawns by discouraging and repelling surface-feeding insects such as chinch bugs, bluegrass billbugs and sod webworms. When using grass seed, be sure to request endophytically enhanced varieties. Moreover, an organic lawn develops an inherent protection mechanism of checks and balances. By eliminating the use of lawn chemicals, natural pest control is encouraged through the conservation of beneficial insects, such as predators like big-eyed bugs and rove beetles.

Thatch is a major contributing factor in the occurrence of insects and disease. It is a layer of partially decomposed materials found just above the soil surface. Thatch is an ideal environment for insects and diseases to flourish. In addition, thatch impedes the movement of water and fertilizer into the root zone. Aeration is the process of mechanically removing small soil cores and depositing them on the lawn. The cores, containing soil microbes, help to speed up thatch degradation while relieving compaction and allowing more oxygen and water to reach the root zone. Natural lawn care does not promote excessive thatch build-up, further reducing the likelihood of disease or insect imbalances.

I hope the practices described here will help shatter the myth that an organic lawn is a neglected lawn. Good luck with your lawn this season and remember that it’s not the end of the world if a few weeds visit, or if chinch bugs help themselves to a section of your lawn. Keep on smiling – even if your teeth aren’t absolutely perfect.


Michael Schmahl is a graduate of The Niagara Parks Commission School of Horticulture as well as The University of Guelph Turf Manager’s Short Course. Michael is the Horticultural Coordinator of Outdoor Images, a full-service landscape company based in St. Catharines, Ontario. He is past Chair of Canadian Organic Growers' Niagara Chapter and the Turfgrass Management Instructor of The Niagara Parks Botanical Gardens.


Copyright 1997. Michael Schmahl.

Reprinted with permission. All rights reserved.

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