Several very good, not-too-expensive paperback books about gardening have been published recently.

"Every Room a Garden," by Alice Skelsey and Cecile Mooney (Workman, 336 pages, illustrated, $6.95). In this book are listed the specific needs for each kind of plant and the botanic names as well as the common ones. It's a complete guide to selection, placement and care of more than 150 different kinds of plants with illustrations to aid in identification.

"Handbook of Wild Flower Cultivation," by Kathryn S. Taylor and Stephen F. Hamblin (Macmillan, 307 pages, illustrated> $7.95 cloth, $4.95 paperback). With more people doing their won gardening, many find that the naturalistic type of planting is easier to care for and more rewarding than the more familiar rose garden or perennial border, the authors say.

Although the estabilishment of wild flower gardens is to be encouraged, they add, to accomplish anything of permanent value in the conservation of native plants, more must be known about-propagating them.

The plant material covered in this book includes only showy species that would attrack the interest of the amateur wild-flower gardener. Plants too difficult or actually impossible to naturalize, such as most orchids, are omitted, as are plants impossible to eradicate once introduced. Each plant description is concluded with notes on propagation.

"Popular Exotic Cacti in Color," by Edgar and Brian Lamp (Collier, 176 pages, beautifully illustrated, $6.95). The cacti pictured and described are all readily available to the home gardener, the authors say. Plants can be purchased from florists and greenhouses or grown from cuttings or seeds.

Most cacti and other succulents originate in low-humidity environments, so these plants are far more suited to centrally heated homes than many other house plants.

Ideally these plants will do best in a small greenhouse, a conservatory or a sunroom. It is also possible to grow them very well in a cellar using artificial lighting. A variety of carefully chosen species can be grown in a raised rockery in the garden year-round, even though they will be subjected to snow and ice during the winter.

"Begonias As House Plants," by Jack Kramer (Van Nostrand Reinhold, 128 pages, illustrated, $3.95). It is a horticultural fact that begonias grow and bloom well in the home, says the author. This is a versatile plant that can be grown with only a little sun and without pampering. And there are begonias for all types of growing, indoors and out.