Floral Fixation
For very dedicated gardeners, winter simply means closing up shop outdoors and reopening indoors. It’s a time for holding over geraniums and fuchsias, taking cuttings from our favorite plants and starting seeds. To accomplish these tasks, we rely on sunny windowsills, banks of fluorescent lights or the ultimate - a greenhouse.
Though plants can be overwintered and seeds started quite successfully near windows and under lights, greenhouses offer many growing features that windows and lights do not. But are they practical for our area?
They are for Sumio and Mii Tai of Spokane. The Tai’s hardworking hobby greenhouse operates all year around.
This time of the year finds the Tais scrambling to make room in their greenhouse for dozens of fuchsias and geraniums that will need to be overwintered. The permanent guests - exotic orchids and houseplants - will have to be shoved into a corner to make room for dozens of football chrysanthemum cuttings to be readied for planting next spring. Come spring, this 10-by-12-foot greenhouse will be bulging with more than 100 milk cartons filled with sprouting dahlia tubers.
The Tais ordered their Northern Light greenhouse from Garden Supply Co. located in Burlington, Vt., ten years ago. It came as a do-ityourself kit, as many mail-order greenhouses do. With a couple of strong friends, assembly was accomplished within a day. The floor was constructed of a one-foot-deep bed of crushed, sharp gravel put down over existing soil. According to Tai, the sharp gravel is not as slippery as smooth or washed stone.
The length of the greenhouse runs east and west. This ensures the greatest amount of light through the extra large south-facing angled window. The walls are double-walled with one inch of air space. An exhaust fan pulls hot air out, while three automatic vents keep air circulating and plants cool.During the hot summer months, the plants inside are shielded by a summer shade cloth that covers the glazed windows.
The greenhouse is warmed through the winter months with a small space heater. The Tais provide just enough heat to keep the plants from freezing - 40 to 45 degrees. They increase the winter protection by surrounding the outside of the greenhouse with 2-inch-thick Styrofoam.
Because of the expense of heating and lighting a greenhouse through the winter months, most area gardeners use their greenhouses as spring propagating rooms. They are opened in February or March and remain open through May. Even during these few months, heat and artificial lighting must be used.
Because of the increased popularity of greenhouses, more of them are being designed with energy-saving materials and devices. There are many companies that sell prefab greenhouses, including two local distributors - Growing Spaces Northwest (239-4527) and Ted’s Greenhouse Kits (292-2109).
Growing Spaces Northwest offers a geodesic dome in three sizes. The domes have a variety of features including a large water tank for thermal heating. They range from a 15-foot-diameter dome at $1,959 to a 33-foot-diameter deluxe model at $8,950.
Ted’s Greenhouse offers quonset hut-shaped houses of different sizes, including a lean-to type. They are constructed of PVC and steel frames and double-walled, corrugated plastic panels. Some type of heat must be used in this house if plants are to survive the winter. Huts run from a 4-by-8 at $429 to a 16-by-16 at $2,415.
If you are handy enough, you can build your own greenhouse. Margaret Caruso constructed her greenhouse from salvaged materials - old windows for the walls and clear corrugated fiberglass for the roof.
No matter what style of greenhouse you like, here are a few pointers:
Design: The more angles your roof has, the more sun rays will be caught as the sun moves across the sky. This is very important during the winter.
Location: Greenhouses need at least a half-day of full sun.
Framing: Aluminum is light and virtually maintenance-free; plastic is used only for temporary buildings; pressure-treated wood is excellent for attaching acrylic and polycarbonate skins.
Glazing: Glass is fine, but it should be insulated, tempered glass, and never tinted. Fiberglass can be purchased flat or corrugated. Soil particles are easily caught up in fiberglass, so wash this material frequently. Polyethylene is used only for temporary structures. Acrylic is excellent.
Electricity: Greenhouses must have an electrical outlet (always to code specifications) for regular and supplemental lighting and heating.
Heating: Electric is the most convenient but is the most expensive. If gas or oil is used, the greenhouse must be vented. All hobby greenhouses should have a kerosene space-heater for back-up heating, in case of a power outage.
Fans: All greenhouse must have good air circulation to ensure healthy plants.
Greenhouses may seem like an expensive hobby in our area, but they offer the gardener a chance to experience exotic orchids, blooming bougainvillea and fruiting pomegranates. And where else but in a greenhouse can you raise literally hundreds of flats of annuals and choice perennials?