If there is one problem all greenhouse gardeners seem to share, it is the need for more room. Inevitably, enthusiasm outdistances growing space. At the start, the empty greenhouse looks enormous but all too soon it is filled to overflowing. One way to gain more room for potted plants is to put up shelves. Suspend these from the eaves along both sides of an even-span greenhouse or along one side and on the supporting wall of a lean-to. You can hang shelves singly or in double tiers, depending upon the brackets used. They can be shelves of wood preferably of 3/8-inch thickness to prevent warping in the humid atmosphere or of glass. Glass is preferred because it cuts off less light from plants in benches below. Also available are attractive, lightweight shelves of perforated aluminum. If necessary, you can install shelves on gable ends of the greenhouse.