The success of a garden depends a lot on location. Sunlight, good soil to which organic matter has been added, no nearby trees or shrubs, and a water supply close by are very important.

Some know-how can make a big difference. Make your plans early in the year for a season-long guide. Successive plantings are desirable if you want to have a continuous fresh supply of certain vegetables.

Don't plant too much of a crop at any one time. Two or three small plantings of leaf lettuce and radishes may be made a week to 10 days apart in early spring with an additional one in the fall. Onion sets for green onions can be planted every two weeks until you have used up all your sets.

At least two plantings of carrots, beets and cabbage should be made, one early in the spring for summer use, another later on for fall storage. Several plantings of sweet corn and beans should be made throughout the season.

Some of the best, inexpensive help can be derived from Plants & Gardens Handbooks published by the Brooklyn Botanic Gardens, 1000 Washington Ave., Brooklyn N.Y. 11225. Each one, 64 to 104 pages, with contributions from experts, well illustrated, easy-to-understand language, costs $1.95 plus 60 cents for postage and handling for the first Handbook and 10 cents for each additional one.

Here are some of the latest Handbooks that can be ordered direct, giving name and number:

"Community Gardening", Guest Editor Robert A. Wearne, Horticulturist Emeritus, Extension Service, USDA, Washington, D.C. 25 contributors, 64 pages, No. 88.

"People now garden because of their preference for the taste of fresh, homegrown fruits and vegetables, and as a hobby that provides both mental and therapeutic rewards for physical exercise and to save money," says Wearne. "Throughout the U.S., athletic fields, jogging trails or tennis courts are accepted in practically every community. Community gardening is even more an essential part of the American way of life."

"Gardening Without Pests," Guest Editor Spencer H. Davis, Jr., Extension Specialist, Plant Pathology, Rutgers University, New Brunswick, N.J. 19 contributors, 88 pages, No. 89.

"When you are ready to set out your garden, read the description of the plants carefully and completely," says Dr. Davis. "Do not make your selection just from the varieties with the prettiest and most colorful flowers. Look in the descriptions of the varieties for the word 'resistant.'

"Look for wilt resistant mildew resistant, virus resistant, etc., when you make your selections and you will have a lot less need for pesticides.

"Much has been done in developing resistant varieties and much more is being done, yet we still have a long way to go.

"As a rule, it is well to add a 'spreadersticker,' to any spray material you will use on glossy -- leaved plants, such as tulip, gladiolus, onion, rhododendron, alaurel and spruce. This spreading-sticking agent gives a better coverage and distribution of the pesticide over the waxy or glossy surface."

"House Plants," Guest Editor Charles Marden Fitch, frequent traveler to the tropics in search of new plants and author of Complete Book of House Plants, 15 contributors, 64 pages. No. 90.

"Using fluorescent lights to supplement daylight or to create indoor light gardens gives one freedom to grow houseplants almost anywhere." says Fitch.

"Some of the most beautiful tropicals are grown in the basement under fluorescent lamps. When the plants are at their blooming best they are given display space in the living room, on a dining room table or in a similar prominent location. Such a system lets me utilize space in an already heated, easily accessible place where I only have to provide adequate light and humidity.

"Even more exciting are attractive light gardens designed to be a decorative part of an indoor living area. For example, a feature of my own living room is a wall-mounted light garden kept in good condition by a combination of early morning sunlight and three 40-watt fluorescent lamps."

"Container Gardening," Guest Editor George Taloumis, Garden Columnist Boston Globe and author of several books, 19 contributors, 64 pages, No. 85.

"Hanging baskets may be suspended from eaves, rafters or from branches above the window which allow the plant to receive more light than it might in other situation," says Everett L. Miller, Assistant Director responsible for the contributors.

"Two important considerations must be kept in mind before hanging the basket. It must not be hung so high that it is difficult to groom, water, or view; and indoors a receptacle for the collection of excess water must be provided so that the surplus water does not drip onto furniture and carpeting. The ideal area for hanging baskets indoors is above some type of non-porus flooring such as tile or cement.

"The good air circulation around hanging baskets causes them to dry out rapidly. Many times the small size of the basket in relation to the size of the plant also makes frequent watering and fertilization a necessity.