There are other people in this world who have expensive hobbies. There is the fellow who bought a bottle of Bordeaux wine for $29,000. There are several people who have invested an entire inheritance in a postage stamp. There are even people who collect coats of small furry animals and necklaces of large icy minerals.

I, however, grow vegetables.

Now vegetable growers are generally regarded as compost-heaping, homecanning, economical folk who feed families of 12 all winter long from one 10-by-10 foot patch of soil.

But I suspect that many of them are really like me, closet extravagantes who indulge their land as they would never indulge their children, with a flagrant disregard for budgeting. People who would - indeed, may - go bankrupt for their green beans.

I thought of this last weekend when I "put in my crops" - an absolutely ludicrous description for planting a patch of urban land that, left to itself, would bear only one native product: rocks.

In order to make this garden defy its nature and please my fantasies of Nature, I again lavished it with the most extraordinary amount of cow manure, peat moss, 5-10-5 fertilizer, hearty seedlings and hopeful seeds.

In short, I invested $35.78 in 250 square feet of land, if you do not count the cost of "Crockett's Victory Garden," a year's subscription to Horticulture magazine, gardening tools, tall redwood stakes, metal tomato cages, my own manual labor and, of course the impending bill from the orthopedic surgeon.

It would have been cheaper to have directly showered the land with quarters and mulched it with shredded dollar bills. It would certainly be cheaper to buy the vegetables.

But I am by now so hopelessly addicted to this plot that if someone told me that spreading beluga caviar over the topsoil would make my cucumbers flourish, I would be on the next plane to the Captain Sea.

And I would not be alone. There are thousands of us, each tilling God's Little Sixteenth Acre with fortune and fanaticism.

There is, for example, a man who began his garden by buying a jackhammer. His only earth was hidden under macadam. There is another perfectly sane woman who hires a couple every July to vegetable-sit while she is on vacation. And there are, I am sure, a dozen more who have taken out home improvement loans to furnish their asparagus with beds.

But we have all come to this state for the simplest and most attractive of all reasons: Vegetable gardening works. It is relatively reliable and relatively controllable. Relative to the rest of life.

The average parent may, for example, plant an artist of fertilize a ballet dancer and end up with a certified public accountant. We cannot train children along chicken wire to make them grow in the right direction. Tying them to stakes is frowned upon, even in Massachusetts.

Gardening is also much more predictable than governing. If you try to fertilize foreign soil with billions, it may ungratefully sprout a generation of antiAmericans. Pour money into an antipoverty program and you may have only nurtured another middle-class bureaucratic weed.

In real life, it is increasingly hard to know what is needed, who the enemies are and what the results of our best efforts will be, whether we are working in science or education.

But in the garden, the cast of characters, the outline of the thickening plot is less complicated. Friends are as obvious as the sun. Enemies are as real as the root borer. The goal is as tangible as a head of cabbage. You don't need a consultant to asses failure and success.

Under those fertile circumstances even the tomato that ends up with a $1 price tag begins to look like a bargain. At least it's one investment you can sink your teeth into.