Contrived by a former engineer, ""square foot gardening"" is a continual-harvest alternative to growing in rows--a practice more appropriate, Bartholomew suggests, to commercial agriculture. His square-foot plot method tends to cut down on weeds, grows more food in less space, and solves the August/September problem of too many squash and tomatoes. The gardener plants, say, four lettuce seeds in a plot, plants a few more lettuce seeds in another square several weeks later, and so on, harvesting them in small batches through the season. Another square may contain one pepper plant or nine bush bean plants or sixteen carrot plants. Some plants, such as zucchini, need larger areas but most can be accommodated. The checkerboard effect is attractive, and the garden seems to need less maintenance time, though there are additional efforts--building small protective structures, or support frames for vertical crops--which can add up. No matter. Though not as entertaining as Sal Gilbertie nor as pristine as the Nearings, Bartholomew is a welcome presence, and his ideas for special gardens--for children, wheelchair occupants, weekenders, etc.--are most appealing.