At least one major cleanup should be scheduled for the greenhouse each year, and the ideal time for this is during the summer, when the growing schedule is at a low point or the greenhouse has been emptied by moving pot plants and baskets into the cool shade of the outdoor garden. If some of your plants require year-round greenhouse protection, it is still possible to move them outdoors for a single day without harmful results if you choose the day carefully avoid strong winds or possible showers, and shelter the plants under bushes or trees to prevent sunburn.
Start the greenhouse cleaning by removing unwashed pots and flats that have found their way under the benches. Store them outside tem-'porarily and concentrate on the interior cleanup. Next, collect all the bottles, boxes, and cans of pesticides, fungicides, and fertilizers, place them carefully in a labeled carton, and store the carton out of the reach of children and pets. If you have small quantities of soil, sand, and other potting materials, removes these also. If your materials are contained in a permanent arrangement of large containers, they may be left in place, but cover them tightly.
If the bench soil must be replaced, empty the benches at this point. Benches of asbestos cement-board should be hosed to remove all particles of soil; it may be necessary to scrub wood benches with a wire brush to remove accumulations of soil. While the benches are empty, wash all glass on the inside with a long-handled brush or sponge. One of the extension-rod car-washing brushes that attaches to the end of a hose will do a very satisfactory job with little effort. Do not neglect the roof glass, though most of the accumulated soil, algae, and grime will be at bench height (and on the glass below benches if your greenhouse has glass to the ground).
Wood-framed greenhouses in need of painting should receive at least one coat of paint on the inside and two coats on the outside to protect them from weather, but the structure must be thoroughly dry before the paint is applied. Use only paint specially recommended for greenhouse use. Any structural parts of steel should be wire-brushed and given a coat of rust-preventive paint. Aluminum-framed structures do not need painting or wire-brushing, as the aluminum used for greenhouses is anodized and maintenance-free.
Motors that operate ventilating and heating equipment should be checked and instructions for their particular care referred to. The heating system should receive its annual inspection and cleaning. Test all thermostats, humidistat, and temperature-alarm systems; check thermometers and hygrometers for accuracy. Replace broken or cracked glass; if your house is putty-glazed, inspect the glazing for voids caused by drying and re-putty where necessary.
If your greenhouse has dirt or a gravel floor, you will probably have a fine crop of weeds growing in corners or around bench legs. Dig the weeds out with a trowel or small shovel, being sure to get the roots. New soil for benches should be sterilized, either before it is brought into the greenhouse or after it has been placed in the benches. Use a specially built sterilizing pit or one of the commercial sterilizing preparations manufactured for this purpose. Fumigate and spray the interior ("how-to" instructions for fumigating and spraying appear at the end of this chapter), and you are ready to restock your greenhouse.
Return only clean pots, flats, and other materials and supplies to your scrubbed, repaired greenhouse. Put the pesticides, fungicides, fertilizers and other chemicals in their proper safe location, and store tools and equipment where they belong. If plants have been summering outdoors, inspect them carefully-tops, sides, and bottoms of pots and plants for slugs and snails, and spray plants to eliminate aphids, red spiders, or mealy bugs. Do this work outdoors before returning the plants to your clean greenhouse.
This cleanup program, if planned and carried out systematically, requires very little time. Your gardening activities will be more pleasant and results will be more satisfactory because of this small time and effort taken from your summer fun time.