OUTDOOR LIVING. `Just say no' to chemicals. Organic fertilizers assist nature for healthy lawns

THE vanity license plate on Mike Merner's station wagon states his passion plainly: GROW. Mr. Merner is a professional landscaper in southeastern Rhode Island. As such he grows and cares for a wide variety of plant species, from the azalea to the yellow-berried yew.

But mostly, he grows lawns - for other people. He's a lawn maintenance expert, in other words, and a very successful one at that.

In recent years his reputation has grown as the man who can produce and maintain a vigorous, healthy lawn that is largely weed- and pest-free.

More significant, to an increasingly concerned public, he maintains lawns that are free of health hazards to people and pets. The children can romp and the family dog can roll on the lawn right after any one of his treatments.

It wasn't always that way. Merner studied conventional turf management at the University of Rhode Island in the '60s - when the theory of the day was that a healthy lawn was impossible without regular applications of herbicides and pesticides. It took him about 14 years to find out otherwise.

Merner followed the all-chemical route when he worked for a golf course. For a few years afterward, he set up as an independent landscaper.

But it wasn't long before he began to notice the deteriorating health of the soil and the increasing frequency of turf problems. It seemed that the problems arose in direct proportion to the destruction of the soil life by the heavy use of chemicals.

``I found that the more I did, the more I had to do,'' he says of those early days. ``I was creating a chemical dependency in lawns'' - lawns that needed a repeated ``fix'' to stay green.

``Toxic rescue chemistry'' is the phrase increasingly used by critics to describe the heavy, all-chemical approach that does nothing to maintain the teeming populations of microorganisms naturally present in a healthy soil. It produces a misleading surface green that belies the lack of substance in the root zone.

So Merner concluded that the key to a vigorous lawn lay in developing a healthy soil and a balanced ecosystem. It took him seven years to slowly drop his lawns' dependence on chemicals and come ``to the delightful conclusion that we do not have to douse the earth with any toxic synthetic chemicals in order to have a beautiful, healthy lawn.''

A growing though still small number of fellow professionals now think along similar lines. Sheila Daar, a landscape contractor and consultant on integrated pest management from Berkeley, Calif., is one of them, but she contends that the feasibility of maintaining an attractive, healthy lawn without the use of pesticides remains one of the ``better-kept secrets'' in the lawn-care industry today.

Eliot Roberts, director of the Lawn Institute in Pleasant Hill, Tenn., has no problems with what he sees as the judicious use of chemicals. Even so, he maintains lawns that have never had a fungicide application in 50 years. ``They have never needed one,'' he says, and doubts they ever will, because of the consistent, if not exclusive, use of natural fertilizers. Organic methods make sense, in his view, ``because they allow and assist nature in building up and maintaining a healthy soil.''

Quoting the title of a book to make his point, Dr. Roberts contends that ``it's the dose that makes the poison.'' Professional lawn-care companies have often been guilty of putting on too much chemical. But by far the worst offender is the homeowner - who invariably ``puts on more, rather than less,'' in the hope of solving his problems. The result is an even more severe lawn problem.

Roberts prefers organic fertilizers, because they never overfeed the grass. Damage to soil life is next to impossible from any reasonable application.

Among chemical fertilizers, he finds those applied in liquid form with a hose-end applicator more acceptable, because excessive, soil-damaging applications are highly unlikely.

Jeff Ball, an author and host in the National Gardening Association's video series, is a convinced compost user, but also has little quarrel with the periodic use of liquid chemical fertilizers on his lawn.

He contends that lawns growing in soils rich in organic matter can accept controlled applications of chemical nutrients. But he avoids herbicides and pesticides that would kill or deplete those all-important soil-forming organisms. Not only do these soil organisms break down dead growth, they prevent the formation of that nemesis of all highly chemicalized lawns - thatch.

This is overly dense, soft growth - from heavy doses of chemical fertilizer - that is most vulnerable to insects and disease, in the view of all those interviewed. To maintain soil life, they use pesticides that are host specific, such as milky spore that attacks only the Japanese beetle grub. It is the kill-everything-in-sight pesticide that has done so much damage to our lawns and gardens, in their view.

Merner is so confident of the overall lawn health resulting from his ``reformed'' approach that he will guarantee any lawn he maintains against insects and disease.

``Initially my system costs a bit more [than the all-chemical approach],'' he says, ``but in the long run I'm far more reasonable, because I have fewer problems to contend with.''

Organic lawns are slower growing, less succulent, and more hardy, in Roberts's view - and require less water to maintain an attractive turf. ``This advantage, alone, often offsets the increased cost of many organic turf fertilizers,'' he says.

Those advocating natural turf fertilizers are all quick to make this point about the more natural system:

Just as it takes three to four years for problems to start surfacing in the heavily chemicalized lawn, it takes about three years before an organic lawn begins to reach its peak. ``That's because it takes that long for the soil life to fully recover from chemical abuse.''

So how can we improve a sagging lawn?

Each turf specialist has his or her own preferences, but most agree on these points:

Dethatch and aerate. If the lawn is troubled by a heavy thatch (the accumulation of a mass of old surface roots which sheds more water than it allows through), it will be necessary to mechanically remove it. Either rent a special machine for this purpose, or buy a dethatching tine that can be attached to a conventional rotary-blade lawn mower.

Light thatch can be biologically removed by top-dressing the lawn with finished compost or rich top soil, or by applying bioorganic fertilizers containing microorganisms that eat thatch. Blending composting microorganisms, available from most gardening centers, with the finished compost is another excellent approach.

Lime and fertilizer. If a pH test shows that the soil is too acidic, top-dress with lime. Slow-release natural fertilizers can be applied at the same time. Avoid using artificial fertilizers right after liming, as the lime tends to volatilize the nitrogen in chemicals.

Milky spore. Make a one-time application of milky spore, a pathogen of the imported Japanese beetle grub. Cinch bugs and sod web worms, which also attack turf grass, are seldom a problem in a biologically rich soil, because the enemies of these pests exist naturally in North American soils.

Mowing. Unless in a dry period where little growth is noticeable, mow the lawn once a week. Set the mower two to three inches high. The higher the top growth, the deeper the root system. There is always a correlation between the two. When an overgrown lawn is suddenly cut short, there is comparable death of the roots.

Weeding. Hand-weed or spot-kill weeds with a herbicide to eliminate unwanted plants, rather than broadcast herbicides over the entire lawn.

Watering. If you want a lawn that's green even at the height of summer, you will need to water it. Never do so more than once a week, but water deeply when you do. The idea is to dampen the soil at least 12 inches down to encourage deep rooting.

Light surface watering is one of the contributory factors to thatch development, as roots grow back up to get the limited water supply. Once thickly formed, thatch, like its rooftop namesake, sheds water most effectively.

Garden centers and farm supply stores are increasingly stocking natural fertilizers along with chemical products.

Mail-order companies specializing in natural fertilizers and biological or host-specific pesticides include:

Natural Gardening, PO Box 149, Sunman, IN 47041; Necessary Trading Company, New Castle, VA 24127; Nitron Industries, PO Box 400, Fayettville, AR 72702; Ringer Corporation, 9959 Valley View Road, Minneapolis, MN 55344; Safer Inc., 60 William St., Wellesley, MA 02181; Trans National Agronomy Ltd., 470 Market St., Grand Rapids, MI 49503.