THE greening of America is changing into a flowering of many colors - especially in the vegetable patch. Beets are not necessarily red. Carrots are often white rather than orange. Gardeners are swapping seeds for such unusual foods as British telegraph cucumbers, pac choi, Mizuna mustard, and Romanesco broccoli.
Even as it gets more upscale, the process of growing things is becoming demystified. Almost anyone can grow arugula or basil in a flower pot. Today's hybrid seeds germinate quickly, and premixed soil comes in handy plastic bags.
This year, 29 million households have home vegetable gardens, and the number is increasing, says Charles Scott, president of the National Gardening Association in Burlington, Vt. The reasons he sees: concern over chemicals and pesticides in commercial farming. People are also growing their own food for taste and freshness and to obtain special varieties not available in local markets. Cost, on the other hand, is not a big factor.
``The swing in home vegetable growing seems to be away from the common garden-variety,'' says Steve Frowhine, a horticulturist with W. Atlee Burpee & Co. in Warminster, Penn. ``The trend is for specialty and gourmet vegetables and fruits,'' he says.
Joan Murphy, a local gardener, is growing yellow raspberries, bright red Swiss chard, and yellow beets in her community plot in the Fenway gardens here.
``Colors give you a variety of serving,'' she explains. ``Yellow beets, for example, can be garnished with parsley, and may taste the same, but the green parsley looks prettier than on red beets.''
Pearl Franks, another Fenway gardener, grows white cucumbers to mix with her red onions for pickles she'll make in the fall.
Blue potatoes, red lettuces, and garnet and white radicchio are popular, as are white eggplant, red okra, Asian pears, purple beans, purple broccoli, and white strawberries.
Supermarkets, farmers' markets, and specialty stores offer some of these new foods, but this year's figures show that much of today's fresh produce comes from the small garden plots of the United States.
The American Community Gardening Association estimates that 90,000 acres of urban land are cultivated by community food gardeners throughout the nation.
In Seattle, the P-Patch Gardening Program is the biggest all-organic community program in the country. Some 25,000 Seattle residents grow at least $200,000 worth of organic produce in 23 gardens.
Of all vegetables, salad greens are the most popular, according to Renee Shepherd of Felton, Calif. Ms. Shepherd owns a mail-order firm that sells seeds from Italy, France, and Holland.
``More people are into salad gardens than anything else,'' she says. Her customers are growing lettuces of unusual colors and textures - radicchio, arugula, sorrel, red romaine, red oakleaf, and red mustard greens are some of the choices. ``The flavors are exciting and different,'' says Shepherd.
``The range of tastes of the American palate has become wider and more sophisticated as people discriminate between the slightly sharp and subtly bitter flavors of dandelion, arugula, sorrel, and rapini,'' she adds.
Among other vegetables, one of her company's popular items is an Italian heirloom plant called Italian trombone squash, or zuchetta rampicante. ``A climber, it's pale green, with firm flesh and is about 12 to 16 inches long, with a flavor like an artichoke,'' says Shepherd.
In Dixon, Calif., Georgeanne Brennan and Charlotte Glenn, a horticulturist, have a specialty seed mail-order company called Le March'e Seeds International. ``Eight years ago nobody was interested in our little white packets of special seeds we'd found in Belgium, France, and other countries - except one little store in Berkeley, Calif.
``But the last 18 months, our business has tripled all over the US. The seed industry has moved in a new direction to meet the growing interest in exotic flavors and gourmet cooking,'' says Ms. Brennan, who coauthored with Ms. Glenn ``The New American Vegetable Cookbook'' (Aris Books, Berkeley, Calif., $14.95), now being revised.
But while people want better, more flavorful food, ``they're too busy to grow it all themselves,'' says Klaus Neubner, executive vice-president of Park Seeds in Greenwood, S.C. ``The committed gardeners will still have their sizeable plots, but the trend is toward container planting and European varieties, specialty plants that won't require as much overall care,'' Mr. Neubner says.
Vegetable plots are smaller, and busy people may do their planting in containers, window boxes, wooden and brick planters, and barrels and pots of all sizes.
``People are doing more intense gardening - using varieties that have high yield in a small space, using pyramid and other shapes,'' says Mr. Frowhine of Burpee.
``For container gardening, there are varieties with small roots,'' he says. ``And space can be saved by growing plants vertically rather than horizontally with A-frame trellises and redwood slat towers.''
Growing herbs has become an ever-increasing passion among all cooks as they discover the beauty, usefulness, and pleasure from these fragrant plants.
``The demand for herbs is unbelievable,'' says Sal Gilbertie, who owns a large herb farm in Easton, Conn., and is the author of ``Kitchen Herbs'' (New York, Bantam, $24.95). Mr. Gilbertie says his sales of herb seedlings and plants have quadrupled in the last five years.
Herbs ``are easy to grow and easy to toss into a stir-fry dish or soup or to use with fish,'' he says, and once you start using fresh herbs you'll know how much better they are than dried.
``The newest popular ones are cilantro and epazote, both used in Mexican and Oriental foods. Rosemary and hot spicy chilies are also favorites this year.'' All-time favorites include tarragon, thyme, savory, chervil, chives, parsley, lovage, and mint.
Paralleling the herbal renaissance is the explosion of cottage industries that supply the demand for fresh-cut herbs and for dried and decorative herb products as well as for gourmet cooking.
``Traditional farmers are switching to alternative cash crops such as chives or shiitake mushrooms, edible flowers, or medicinal herbs from soybeans, corn, and other plants,'' says Maureen Buehrle, executive director of the International Herb Growers and Marketers Association.
Even Amish farmers have hitched onto the pesto bandwagon. In 1983 the Plain people of Lancaster, Penn., started planting whole fields of basil for commercial sale.