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Jan 20, 2024

Buy or build a hobby greenhouse now for winter beat supply chain kinks

We are still in August so even as we focus on watering, planting the rest of our fall vegetable garden and pre-emergent weed control, we begin to think about the winter ahead. If you have a hobby

We are still in August so even as we focus on watering, planting the rest of our fall vegetable garden and pre-emergent weed control, we begin to think about the winter ahead.

If you have a hobby greenhouse or conservatory, this is the time to get it ready for winter. If you don’t have a hobby greenhouse and have been dreaming of getting one, you need to move fast to build or buy one before winter.

With all the supply chain challenges right now, there is no time to waste.

You need to decide where you will locate the greenhouse. Will it be freestanding or will it attach to your home, garage or another building? Will you build your own greenhouse, buy a kit to assemble and install or have your greenhouse custom built?

Most home-built greenhouses are wood frames, and most kits or pre-engineered greenhouses are galvanized steel or aluminum frames. If you build your own with wood, consider using redwood, cedar or pressure-treated wood to assure a long life for the frame in the high humidity of a greenhouse.

Pressure-treated wood will tend to warp or bow in a greenhouse over time with the extreme heat and moisture cycles. Most greenhouse kits or commercial packages are framed with metal for extra strength and rigidity. Be wary of the lightweight metal or plastic frame kits, which do not secure well or hold up long-term in our gusty winds.

Always use aluminum or galvanized steel to avoid or slow rusting problems. If you frame with red steel, you must primer and paint the metal to slow rusting in the high humidity of the greenhouse.

Selecting the glazing or skin of the greenhouse is one of the most important decisions as it impacts light transmission and the amount of heating required for the greenhouse.

A double-layered glazing will condensate less and reduce heating bills by a third or more than single-layered glazing. The most popular double-layered glazing for hobby or estate greenhouses are polycarbonate panels, usually 8mm (about ¼-inch) thick and available in 4- or 6-inch widths in lengths up to 24 feet long.

The sheets look like many square soda straws gathered together in one flat panel. The “soda straws” have to run from top to bottom so any condensate between the top and bottom layer can drain to the low end.

We suggest using greenhouse grades of these panels that will have extra UV protection on the top side to prevent yellowing and anti-condensate treatment on the inside layer to prevent large water drops adhering to the surface as on a tea glass.

We believe it is better to use clear panels so we can get as much light as possible in the dark winter months and then we can use shade cloth to reduce the extreme light and heat of our bright summers.

Other choices in double-wall glazing include acrylic panels like those used on the Myriad Botanical Gardens' Conservatory and insulated glass, which is quite beautiful but much more expensive and requires extra framing to support the extra weight.

It is less expensive and easier to install single-wall glazing, but it provides less insulation and will require more heating equipment and bigger gas bills. The most popular single glazing was single-wall tempered glass, then corrugated fiberglass and now corrugated polycarbonate, which is available with extra UV protection in a greenhouse grade.

A fancier option is corrugated acrylic. Clear corrugated PVC panels are used on many import kits, but they yellow within a few years and are much more vulnerable to hail damage.

The least expensive greenhouse glazing is plastic film and many grades are available that last from a few months like lumberyard poly to four years and offer different light diffusion properties. They perform best on rounded roofs like Quonset or barrel roofs and last longer and reduce energy if installed as two layers with air blowing between the two layers. The poly film does not work as well on sloped or rigid peak roofs in our Oklahoma high winds.

Make sure to check if a building permit is required to add a hobby greenhouse to your property. Besides the structural framing and glazing, you will need to provide ventilation, heating and cooling, as well as shade cloth and temperature controls to get the best use from your home greenhouse.

Rodd Moesel serves as president of Oklahoma Farm Bureau and was inducted into the Oklahoma Agriculture Hall of Fame. Email garden and landscape questions to [email protected].