GROWING GREAT ASPARAGUS. For thousands of years, these bright green spears have been the royal vegetable of spring

ON the 15th day of March, as he does every year (give or take a day or two), Dick Raymond took out his high-wheeled string trimmer and mowed down the winter-killed fronds in his asparagus beds. Then he returned indoors, marked down the event on his gardening calendar, and mentally calculated when the first tender spears would make it to the table. They wouldn't be all that long in coming.

It didn't matter that a brisk northerly wind had brought finger-numbing temperatures back to the region or that snow still blanketed most of the state: He would almost certainly be harvesting asparagus in six weeks' time.

Moreover, the first spears in his garden - some of the first in all Vermont - would come from an asparagus bed that Raymond describes as ``that happy accident.''

This is how it happened.

A gardening store in Burlington had a fairly large inventory of asparagus crowns left over after the spring planting season. It had planned to toss them in the garbage.

This sounded like a terrible waste to Raymond, so he offered to take the crowns and simply heel them into a corner of his garden from where they could be lifted the following spring and sold.

As Raymond recalls it, he ran the tiller over the ground once, made a few shallow furrows in the soil, and dropped in the crowns. Once the fronds were up, he mulched the bed well and left them. Finally, the garden center said thanks - but not to bother. It had ordered all new crowns for the following year.

So now Raymond had what he thought was an ill-prepared, poorly planted asparagus bed that would need replanting the following spring. But then something interesting happened: The hastily heeled-in bed was the first by far to produce fat, edible spears the following year. Moreover, it yielded abundantly and has continued to do so ever since.

What occurred more than 10 years ago challenged some of the long-accepted rules of asparagus culture: that of deep planting. As Raymond found out, deep-planting isn't all-important after all, nor is any undue care required.

Simply toss in the crowns, cover them up, and they'll do just fine. Consistently good harvests over the years validate those findings. Recently some scientists at the United States Department of Agriculture come to similar conclusions.

Raymond reasons that the surface soil warms up first in the spring. This sets the shallowly planted asparagus off and growing - days and even weeks ahead of the deep-set plants.

Meanwhile, Carl Cantaluppi, a horticultural adviser to the University of Illinois Cooperative Extension Service, has come up with similar findings.

His studies show that while surface-planted asparagus doesn't produce quite as many extra thick spears as the deeply planted plants, it produces more in total weight of edible spears in a season.

Mr. Cantaluppi says that however carelessly the asparagus crown has been planted (even upside down), it has a remarkable ability to adjust and get on with the business of growing. That's the same message Ruth Stout, pioneer of no-dig, deep-mulch gardening, gave out decades ago.

In her ``No-Work Garden Book,'' Ms. Stout said: ``Since I had long ago lost faith in the so-called experts, I bought two dozen asparagus roots ... and decided to try planting them by just laying them on the top of the ground (in a bed of peonies) and tossing hay on them.'' She went on to say that she enjoyed ``a fine crop from these roots every season.''

Some of the latest findings also suggest that regular applications of nitrogen fertilizer are not necessary.

But all agree the foundation of a good, long-lasting asparagus bed is to get plenty of phosphorous into the soil. Since this element moves very slowly through the soil, it needs to be placed right at the start where the roots are. The soil should also be adjusted to just about neutral (between 6.5 and 7 on the pH scale).

So incorporate the necessary amendments (phosphate rock, ground limestone, or both), plus organic matter in the form of old manure, compost, decomposed straw, etc., when first you dig or till.

Make furrows, as deep or shallow as you want, 5 to 6 feet apart. Set out the crowns 1 to 2 feet apart. Within a few years the plants will spread, until the whole area is one solid asparagus bed.

As soon as the first fronds are growing strongly, lightly mulch the bed with hay or shredded leaves. Add more mulch in summer. The mulch will keep down competing weeds and will steadily decay, improving the soil.

Repeat the mulching process every year after the spring harvest, and the mulch alone will probably provide all the nutrients your asparagus bed will need.

The first spring after planting, the harvest should be light - about three weeks long. Thereafter, you can pick this universal favorite for a full eight weeks each spring. And when finally you need to start thinning the beds, you can pick all season long from those plants you intend to throw away.

How long can you expect your asparagus bed to last? Ruth Stout talked of a 35-year-old bed. Dick Raymond sees 30 years as a perfectly reasonable life expectancy.