These openings, 11/2X16 inches, have window screen tacked to the outside to keep out insects. Four wooden strips 1/4x2x 17 inches, fastened over the inside of the openings, cover the ventilators. These covers, or shutters, are secured with a single screw and can be pushed open to admit air. Humidity can be increased by spraying plants with water, and by adding water to the pebble tray.

   Building a greenhouse or putting together one of the prefabricated ones is not a tremendous project. The greenhouse can be attached to a dwelling, or it can be a free-standing unit.

   I built my first small lean-to greenhouse when I was twelve years old. This 6x9-foot plastic-covered structure cost only $70, but it housed many plant treasures-begonias, geraniums, gloxinias, oxalis, and arnaryllis. Today it continues to give pleasure to my parents.

   My present greenhouse is attached to an east-facing bedroom window of our home. It has an even-span roof, is 10 feet wide, and extends out 20 feet from the house. I spent about a week putting together this greenhouse, a prefabricated model which came complete with cooling, heating, and humidifying equipment. I supplied the foundation, a pebble-surfaced concrete floor, and redwood benches.

   The first step in acquiring a home greenhouse is to check local building restrictions. Write for catalogues of home greenhouse manufacturers (pp. 301-05). After placing an order, you will receive a blueprint of the greenhouse. With this information, it is possible to proceed with foundation construction. Some greenhouses have glass extending to the top of the foundation at ground level; others have glass to the top of a wall that extends three or four feet above the foundation.

   If possible, locate an attached greenhouse so that it has an eastern and a southern exposure to admit maximum light. Too much light can be controlled, but the only way to bring additional illumination to heavily shaded greenhouse areas is by adding fluorescent lights.

   Once completed, the greenhouse will need utilities such as electric wiring, a heating unit, and plumbing. A cooling system is not absolutely essential but it makes for easier greenhouse gardening during warm seasons. A floor of concrete, brick, or gravel will be necessary, as well as benches to hold the plants. Shading to keep light from burning the plants is part of maintenance from spring to late fall. This can be regular greenhouse whiting powder stirred into water and brushed on the outside of the glass, or wooden slats, or roll-up reed screening. I use Lumite Saran shade cloth because it is inexpensive, long-lasting, and comes in several types of weaves to comply with various lighting problems.