Three years ago I visited the home of Willis Bulen here in suburban Minneapolis and examined the lush green lawn carpeting the front yard. A neighboring yard was similarly covered in satisfying green.
Two soil probes quickly showed that what looked similar on the surface was vastly different below leaf level.
The first lawn appeared completely free of thatch and the grass roots had penetrated deeply into the soil to the full length of the probe; the probe of the neighboring lawn revealed heavy thatch and a concentration of roots right beneath the surface of the soil.
Moreover, while moisture had penetrated to the full depth of the probe in the first lawn, it had failed to penetrate the thatch in the second. The soil surrounding the roots was dry to the touch despite a heavy thunder shower the night before.
''No,'' said Mr. Bulen, he had not watered the lawn the day before nor had he watered it in many weeks as regular summer rainfall had provided all the moisture his lawn required. But this had not always been the case, he said. Two years before he would turn on the sprinkler and watch in frustration as most of the water flowed steadily down the gently sloping lawn into the street out front.
A heavy thatch slowed down water penetration to such an extent that he needed to use the sprinkler several times a week to keep the lawn green. In short, the thatch in the lawn had shed water almost as effectively as on the roof of an old-fashioned English cottage.
What changed Mr. Bulen's lawn was several applications of an organic fertilizer, complete with enzymes and composting bacteria, which, over a two-year period, had eliminated the thatch and produced the sort of soft-soil conditions in which a lawn will thrive.
Suburban society's desire for a lush green lawn with the deep-pile comfort of a quality carpet has led to a need for repeated applications of fertilizer and weed killers, plus regular watering if rains are not adequate. The results of this treatment are impressive.
The lawns become green and healthy almost overnight and stay that way for several summers. But slowly over a 5- or 6-year period thatch - the matted accumulation of living and dead tissue at the surface of the soil - builds up to the degree that water penetration frequently becomes a problem and conditions for the development of fusarium and other damaging fungi arise.
It's a known fact that lawns that are not heavily fertilized do not develop thatch. But heavily fertilized lawns invariably do.
Why this should be is not known for certain but it is suspected that, with fertilizer applied on the surface, plus frequent waterings, the grass roots become ''lazy'' and accumulate at the surface.
With no deep root penetration going on the soil beneath the grass slowly compacts. To beat the problems it is recomended that thatch be removed - manually by vigorous raking each year or by attaching dethatching devices to a rotary lawn mower - and that the lawn be periodically aerated by spiking.
Mr. Bulen, manager of a major garden center until his recent retirement, was well aware of how the problems associated with heavily fertilized lawns would have to be tackled when he was approached by the Ringer Corporation of nearby Eden Prairie, Minn.
Judd Ringer, the company president, asked him to experiment on his own lawn with a biologically active product that the company was developing. Preliminary results suggested the product would effectively tackle the lawn-thatch problem.
Mr. Bulen admits he was skeptical at first. Removing thatch by anything other than physically forceful means appeared like a dubious ''wonder product'' to him.
Nonetheless, he agreed - and slowly his lawn did indeed respond as the bacteria and enzymes ''ate away'' the thatch over a two-year period, converting it to a moisture-absorbing humus.
Soil probes showed that the compacted earth beneath his lawn slowly loosened and roots moved deeply into the subsoil in search of nutrients and moisture. His lawn was no longer as vulnerable to dry spells as it had been previously. Now he says his lawn is as green as it ever has been with far less effort on his part.
Repeated trials with Lawn Restore, as the product is called, have achieved similar results in various parts of the country. Some lawns react more rapidly to the application than others. Why this should be is ''something we can't yet answer,'' says Don Loveness, the microbiologist principally responsible for the development of the lawn aid, but overall results have been satisfactory.
Currently, a major East Coast golf club is trying out the product. Its once verdant fairways now are giving so much trouble that a proposal to skim the top two inches off the entire course and replace it with new sod is seriously being contemplated. If anything like the Bulen success is forthcoming, the savings to the club will be immense. Six weeks into the test, indications are promising.
To the best of my knowledge there is no similar biological lawn product on the market at this time. For more information write: Ringer Corporation, Flying Cloud Road, Eden Prairie, Minn. 55343.