Mulching your garden the Mayans' way

Jack Miles Langston is a pharmaceutical marketing expert, which is of no great importance to gardeners. But the fact that he is an innovative horticulturist by avocation is important. So is his birthplace: Mexico City.

You see, Mr. Langston, a Purdue University graduate, combined his interest in growing things with an appreciation of Mexican, particularly pre-Columbian, history. Mayan farmers, he discovered, spread banana leaves (to retain soil moisture and keep out competing weeds) over the land, planting their crops in individual holes dug through the banana-leaf mulch.

They fertilized holes, not the whole plot - and produced food abundantly.

The idea appealed to Mr. Langston, who never did like the idea of spading over, or even rototilling, a large garden. And weeding wasn't his idea of fun, either.

So he substituted black plastic for the banana leaves, added some other refinements, and developed what he calls the Lexigrow system of gardening, ''a sophisticated adaptation of a horticultural process used by the Mayan Indians.''

Using the system, Mr. Langston has consistently won awards at the Indiana State Fair. Recently he wrote a book about it: ''Lexigrow, a New and Easy Gardening Concept,'' published by Lexigrow International Corporation, Indianapolis.

Publicists describe the system as unique. That's a debatable claim, however. Gardeners with no knowlege of the Mayans have come up with the individual-planting-holes idea all on their own. Back in 1963 when I lived in South Africa, I grew a crop of cabbage and cauliflower that way, using newspaper as the mulch. And I've done the same thing with tomatoes on this side of the Atlantic.

But the Lexigrow system is a good one, and my own experience confirms it.

Mr. Langston has brought a tidiness and an organization to the system, describing it in detail so that it can be readily applied to large or small gardens. He has even adapted it to container gardening. His choice of black plastic for the mulch also offers some protection to plants on frosty spring nights as it stores some of the sun's heat, releasing it at night.

People with heavy clay soils that warm up only slowly in the spring might mulch with very wet newspaper to cut out the light, then cover this with a clear plastic that will let in the sun's heat and hold it there after dark, much as happens in a greenhouse. This heat is conducted through the wet paper to the soil.

Tests at the experimental farm of Organic Gardening magazine's publishers show some very positive results from growing plants directly in sod that has been killed by a mulch.

This year, too, I am experimenting by setting out various plants in a ''sod'' of winter rye. The rye was sown last fall and allowed to grow more than a foot high this spring before it was bent over and mulched out of existence with newspapers covered by shredded leaves.

Using a bulb planter, I cut round holes in the resulting sod, added a little compost, and set out the plants: cabbage, lettuce, and peppers. Early results appear promising, and I will have more to say on this method in the fall.

Meanwhile, it seems that the Mayans were on to something pretty good when they introduced banana-leaf mulching to the world.