All gardens, at least all private gardens in towns, are secret gardens, and the secret is that here the gardener enters a world as strange as that of a fish and as beautiful (to the gardener) as the Andromeda nebula. And, of course, sometimes as whirling and unsettled. The tone of these paradises may vary, according to the gardener's vision, experience, taste and, alas, circumstances. A garden that must be shared with terriers, hounds, children, cats, wives or similar obstacles will rarely achieve the undiminished clarity the gardener hopes for. Still, any garden is better than any house and certainly than any business office.

The best results, the greatest delights, come from having the garden completely enclosed, preferably by a fine old brick or stone wall or, failing that, by a decent high wood fence or (as it may be) a chain link fence covered with autumn clematis or ivy or polygonum or dense climbing roses (such as 'New Dawn') or wisteria, though the most vigorous vines will require shearing back when they threaten to leap from the fence and occupy the open space of the garden.

Roses are particularly thorny occupants of such fences, and while beautiful in bloom, require heavy pruning if they are not to bulge out farther than you like.

However it is done, whether by walls or climbers on fences or by screens of shrubs (hollies, yews, viburnums, osmanthus, pink locusts or photinias are admirable choices since many of them are evergreen and the others give a bonus of flower and fruit), the first step is to think how the garden may be shut off from the outer world, at least psychologically if not literally.

It can happen that the small town garden is completely overlooked by windows of neighboring buildings on all sides. The answer to that is not to plant the tallest and quickest-growing evergreens you can think of (such as the Leyland cypress) but to build a shelter or summer house, roofed over with grape vines or wooden slats or what you will.

Which brings us to a critical feature: the place to sit and admire the heaven spread before you. In a tiny garden back of a row house, the sitting place may be nothing grander than a bench or two chairs, sheltered by an overhanging arbor of vine- clothed posts and lintels, out the kitchen door. Importance and dignity are given such a small arbor by setting it on pavement of rectangular- cut stone or brick, or on concrete textured and perhaps softly colored (it is well to avoid intense hues) buff or gray.

The center of the small garden is usually kept open, with the shrubs and creepers around the edge--that is, the small, low plants go in the middle and the hollies and vines go on the walls or fences. But the center is not to be empty, of course. If it suits the tone of the house and the outlook of the gardener, the center might be an old-fashioned parterre of clipped box, the beds shaped like anything you wish and filled in with gravel. Or the beds might be devoted to garden pinks or snapdragons or floribunda roses (continually blooming and colorful and relatively disease-proof varieties such as 'The Fairy' are fairly labor-free).

Or you might not want flower beds at all. The Japanese grow marvelous flowers but usually only in rows as if they were a farmer's peas. They want their real gardens to suggest the serenity or magnificence of nature, and pay virtually no attention to flowers. They concentrate on leaf colors, textures and, especially, stone and water. This approach is by no means limited to the Japanese, and the gardener does not have to start hauling out stone lanterns to achieve the wild and beautiful look. Quite ordinary things such as Boston ivy on a wall, and a few grasses (investigate the genera Miscanthus, Phalaris, Carex, Pennisetum) will give not only delicate effects but a great deal of variety as the year advances. Many of them are beautiful in winter, even when the stems are tan or withered, and many of them are ornamental with their seed plumes, and all are beautiful in snow.

In a sunny spot in the middle of the garden nothing is much prettier than a sitting place sheltered by common grapes (you might as well plant one that has better fruit than most grapes produce, such as 'Villard Blanc,' but remember that most grapes require spraying if they are to have flawless clusters; and there is nothing wrong with the beauty of wild grapes out of the woods). Or a well-behaved and not too rampant climbing rose such as 'Golden Showers' or a Carolina jasmine if the site is sheltered or an akebia vine with little mulberry-colored blooms in April--not showy but pleasant, followed by fruit like blue duck eggs, only longer.

Or, if the gardener is in love with lawns, a panel of plain grass that smells wonderful when it is cut (and there, if you ask me, is the rub: it has to be cut and fertilized and watered if it is to look good enough to justify a central place in the small garden).

Best of all might be a fish pool. Swimming pools are ugly. Go swim in the bay or join the Y or something. How pleasant it would be to have a pool occupying most of the open space of the garden, built of concrete and two feet deep, and devoted to water lilies readily available from aquatic dealers. And fish. Not only common goldfish (as beautiful as any, surely) but also shubunkins and comets and koi and black moors winter over pretty well outdoors in the gentle favorable climate of Washington.

The only thing is, give it some thought and read a few books from the public library on the subject before starting. And much is to be said for quite small pools. They can be informal, as well as rectangular or circular, and when sensitively treated can suggest a woodland stream, maybe with stepping stones and maybe not, and with any number of low-growing plants in the stones around them.

In a tiny sunny town garden in which the gardener wants a sense of stomach, as you might say, and a sense of sweat, a vegetable garden is splendid. There can be tomatoes, the most rewarding of home vegetables, and a few bush beans. There can be the new cucumbers that grow and fruit even in a flower pot --I tried them with surprise and pleasure once. And there could still be things like petunias and nasturtiums to give color among the vegetables, or, if you sit outdoors on summer nights, nicotiana and night-blooming stocks and tuberoses planted in May and dug up in early November and wintered in the basement for planting out the following year.

The critical thing is to think what would be most wonderful and then to go at it without wavering off in a dozen contrary directions. On the other hand, a little garden all jumbled up may be the thing. A tomato here, a rose there, some water lilies yonder, and some grapes and honeysuckles and beets and lettuce rammed in under the roses and a mutt asleep on the young hollyhocks. With spring-flowering bulbs beneath everything else. And it's just plain paradise, only you wouldn't want a newspaper photographer or anybody snooping about.