September in the Small Greenhouse

September is the month when outdoor gardening activities slow down and under glass gardens take the spotlight. If you do not own a greenhouse, this is the best time to purchase or build one. The prefabricated home greenhouse, in exciting new designs, are inexpensively priced.

Since this is the time to empty and clean the greenhouse, see if you can rearrange yours to allow more space. Cleverly placed shelves, benches, or lighted corners can double or triple your growing area. When doing this, move plants out of the greenhouse to give it a thorough cleaning. This includes cleaning surfaces of algae.

After this is done, proceed to clean and make repairs if needed. If you have sand in your benches, either dump it out, sterilize it or bring in a fresh supply. I set my potted plants on pea rock, which I shovel out, wash with a hose and disinfect with bleach. It makes short work of slugs, snails and wireworms. Also have your greenhouse heating system checked. Imperfect flues, rusty pipes or out-of-order alarms can cause winter havoc. Likewise remember to store a quantity of soil. In January it’s not much pleasure digging frozen soil.

If you have extra space in your potting room, install a cabinet to hold pots, fertilizers and sprays. It makes for easier maintenance. During winter, shading is not a problem. From December into early February, many plants grow well with little or no shading. Summer rains usually wear away much of the shading applied in the spring, but if you feel too much remains, add the task of reducing the shade.

When it comes to ventilating, September is tricky. We have days as hot as July, others that are nippy. Automatic ventilators, operated by a thermostat, take care of this problem. As temperature varies, they open and close vents automatically. Manually operated ventilators should be left open a bit even when the heat is on. For hairy-leaved plants, install a mixing faucet, for the temperature of the water can be controlled, thus leaving no marks on the leaves.

By now many spring-potted plants have outgrown their containers. Before knocking them from pots, give a thorough soaking, let the soil settle for about an hour and they will slip out of the pots with the ball of the roots intact, ready to repot into a larger pot.

A coldframe adds much to greenhouse enjoyment. In it you can store potted bulbs, such as tulips, hyacinths and daffodils. As they root, bring into the greenhouse to bloom. Collectors who grow but one kind of plant do not have the shade-and-light problem faced by those who grow a wide assortment. My selection of plants is varied, but all of them grow well in daytime temperatures of 70° to 75° F. and a night temperature of 60° to 65° F.

My greenhouse is small, 10′ by 12′, with a 6′ by 10′ annex, which houses the boiler, potting bench and utility cabinet. This has one wall of south windows. Previous to this year, my greenhouse was the two-bench type, with benches running east and, west, facing north and south. Glass shelves along the north and south sides gave some extra room, but did not help the shading problem.

This year I installed a double-deck system. This gives more room and helps with the indoor shading. A bench, 10′ by 2′, with a galvanized metal tray, three inches deep, sets on legs about two feet above the first level bench. An area of about 15″ close to the windows and another of similar size at the edge of the first level bench receives full light. All the plants on the top deck receive maximum light. A similar bench was installed on the north side. A space about two feet long was left at the end of each of the first level benches to accommodate tall plants of hibiscus, abutilon and clivia.

I place on the top deck all potted seedling gloxinias, tubers that have started, plants which have finished flowering and are ripening seed, potted lemons, oranges, figs, Surinam cherry and strawberry guava.

Passion and rosary vines, plectranthus and pilea help cover the edges of the pans. Close to the windows on the bottom bench grow amaryllis, gloxinias and red-fruited Rivina humilis. The top deck shades some of the area on the first level bench and here I grow African violets, kohleria and achimenes.

Additional space can also be gained by hanging baskets from the ceiling and sides of the greenhouse. Their contents will be dictated by the amount of light reaching them. Orchids, ferns, columnea, aeschynanthus and African violets are a few of the effective hanging basket subjects.

If you desire space without making structural changes, why not add fluorescent lights? Installed under benches in the growing range or potting shed, they are effective for fostering foliage or flowering plants, cuttings or seedlings. I have two lighted propagation areas, which otherwise would be “catch-alls.”

Under the windowsills in the annex two 40-watt fluorescent lights provide “sun” for seedlings. This year I am trying eucomis (pineapple lily), agapanthus, watsonia, tigridia and some new begonias. In the other lighted area, still under these windows, two 40-watt fluorescents furnish light for cuttings growing in a sand-filled terrarium. A friend has lighted metal cases which slip under the benches directly on the ground. This arrangement adds a third more room.

Gardeners who do not want to install lights can brighten dark corners with handsome shade-loving plants. If you are assembling a collection of these try some of the new kinds. Among these plants are those with richly textured leaves, others with dramatically patterned foliage.

Some that I enjoy under the benches are elegant red, purple and silver Cissus discolor and silvery-leaved C. albonitens ; episcias, whose frosty, bronze or waxen foliage makes them ideal under-bench carpets; Anthurium crystallinum, equally at home under the bench or in partially shaded upper areas.

Then there are the handsome rex begonias, which I grow in space-saving flats. Although they do not turn into specimen plants, they brighten up shady spots. In areas which I receive filtered sun try some of the variegated ivies. Under-bench space is good, too, for rooting flats of African violet leaves.

If you are a northern under-glass gardener and feel that your fuel bills have been too high, perhaps you should switch your allegiance to different types of plants, which can be grown in a cool or cold greenhouse. You can enjoy an early spring extravaganza by planting many bulbs, corms and tubers. During this month pot allium, anemone, brodiaea, crocus, daffodil, freesia, fritillaria, gloxinia, iris, hyacinth, lachenalia, narcissus, ranunculus, scilla, tigridia, tulips and zantedeschia.

by Peggie Schultz

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