WE ALREADY KNOW that we should speak kindly to our house plants, and play soft music to them when they droop. This book is a plea that we pay more heed to the weeds -- especially the ones called amaranth. p

Amaranth? The name derives from the Greek for "immortal" and "not withering," writer John Cole tells us. There are more than 60 species in all, and they grow almost everywhere on earth, except around the poles. They survive heat, cold, rain, drought, dust and mud. They range from "ornamentals" -- the spectacular feathery plumes of red and purple and gold that grew in monastery gardens in the Middle Ages, and graced the altars of cathedrals -- to lowly "pigweed" that most gardeners pull out of the cabbage patch and throw away. Under names like love-lies-bleeding, cockscomb, Joseph's coat and prince's feather, they flourished in colonial gardens here, from Jamestown and Williamsburg to Cape Cod -- until a Victorian flower book warned that love-lies-bleeding drew lightning, "and should not be planted near a house." The Hope indians make dye from amaranth; in Honduras they wrap the seeds in a packet to be worn near the chest to ward off colds; in China they call it millet from heaven.

But the reason for this book, and the reason that agronomists, plant scientists and the people who worry about feeding the human race when the world population has doubled, which it's programmed to do by about 2001, are thinking more and more about amaranth these days is that the seeds from some amaranth species contain the highest quality of protein of any grain -- ahead of soybeans, corn, whole wheat and even cow's milk. They are free of the artery-clogging fats of meat and dairy products. The ratio of the amount harvested to the amount sown is greater than for any other commercial grain crop, and the tender green leaves can be eaten like spinach. They even taste good. In parts of West Africa, they are the leading green vegetable. Euell Gibbons commends them in Stalking the Wild Asparagus.

With all that going for it, where has amaranth been all our lives? Doomed by its own mystique, that's where. "Incredibly," Cole writes, "in whatever culture, on whatever continent, in whatever time," amaranth has been seen "as something more than merely a plant; it has become a symbol, a medicine, an icon." So in this hemisphere it was not only the leading food crop of the Aztecs, but was thought to have magical powers and was central to their ceremonial pageants. a huge idol of amaranth dough was fashioned by temple maidens to be carried in processions and later broken up and eaten by the crowds -- an "edible icon," as Cole says. When Cortez and his men annihilated 240,000 Aztecs and destroyed their city of Tenochtitlan, they also wiped out the amaranth crops -- symbols of an alien culture and a pagan threat to the church. Grain amaranth survives in Mexico today mostly in the form of "alegria" candies -- made from popped amaranth seeds and honey (recipe supplied in book).

An though amaranth crops are abundant, the seeds are small and not easily harvested by machine. Wherever industrial farming techniques have spread in the world, amaranth has given way to the few crops that can be grown on huge farms and harvested by a few men at the helm of the massive combines. In the mid-19th century, there were some 40 or 50 crops grown around the world, Cole points out. Today 12 crops "stand between the planet and starvation."

In Cole's view, industrial-age agriculture, with its energy-guzzling machines, has outlived its time and doesn't work. Oil is a finite resource. More people are hungry in the world today than five years ago. And if oil costs keep climbing, can Americans afford to eat machine-cultivated carrots from California, transported by machine to Maine?

Our best hope, Cole argues, is to shift to "postindustrial" farming -- smaller, "varied, low-energy, labor-intensive" farms that service community and regional markets, growing crops that "will grow well with a minimum of care, will have generally high yields, and will be planted in relation to how well fitted they are to a particular environment, rather than how well they can fill the demand which advertising has created for a particular taste." Crops like amaranth.

He isn't just dreaming. The scientific community is researching the world's "forgotten crops," with amaranth high on the list. The Department of Agriculture is testing it; Cornell and other universities are researching it; seed companies offer it in their catalogues (names, addresses, growing instructions and recipes supplied in book). The Rodale Organic Gardening and Farming Research Center is crossbreedig and studying amaranth strains, and a volunteer army of 14,000 readers of Rodale's Organic Gardening magazine are growing amaranth in their back yards in all 50 states and Canada and filing their reports to headquarters. Rodale press has published this book and the Rodale organization supplied much of its research.

This close family connection may account for the drawbacks of the book. It is full of fascinating material that just grows wild on the page. The text circles back on itself to make the same point several times. Some of the quotes are so long you can't tell where they end. The writing can be needlessly coy. (The human body is "a sensitive and complex mechanism if ever there was one . . .") But with all its faults, it tackles a subject central to our lives that most of us haven't thought much about, and it deserves to be read.