For some gardeners, an abandoned patio door used as a cold frame is enough of an edge to healthy frost protected starts. My grandfather who grew one of the most prolific truck gardens imaginable used two abandoned sash windows for his starts. He lived in a milder climate than we experience here in the Rogue Valley.
Had he been able to, he would have devoted a small part of his land to a greenhouse, much like he did with his compost bin.
The reasons for so many types vary from so many crops, to hiccups like what is easily shipped. What is essential to the first time buyer is to match gardening goals with the right product We hope to help you do that just that, even if it means showing the serious gardener a technique that puts a breathing greenhouse in reach of most everyone,
Steel frame greenhouses evolved as wooden framed, glass glazed, poly glazed, models fell out of style. While there is still a market for Cedar framed kits, one only has to look to what the commercial grower has adapted to, to see why today, galvanized steel is the most cost efficient. The frames can be recovered in excess of 40 to 50 years. Depending on what you choose to cover it with, recovering can be limited to 4-5 times over the life of the frame. Little to no hail damage, easy to install, best value for the commercial grower.
Aluminum greenhouses come in two very different types. The majority are made in China, feature polycarbonate walls and roof, with a small door and skylights for climate control.
Some are available with jalousie windows as well. The other type is those available using the same style and strength of extruded aluminum used in storefronts. Here the glazing options run from single, dual, triple wall polycarbonate glazing to exotics like fritted glass that is tempered. The doors are often of a more comfortable size. They come available with interior shading systems. Many are considered contemporary conservatories. When added to the south facing portion of your home, many people find it convenient to remove their patio doors, and enjoy the solar gain.
Cedar greenhouses are now sold mainly as kits that can be shipped easily. Being that the Cedar is covered against the elements, the decay properties are superior to pine or fir. However, the humidity of the interior of many greenhouses makes wood less than first choice for longevity. Though designs exist for larger Cedar models, using a truss method of spanning the length, the trade off is a larger pattern of shadow, and sometimes the need to run a center beam to help bridge the load. Check the many How to You Tube videos, the plans available in Mother Earth News and publications like Fine home Building by Taunton Press.
For a season maybe two, PVC frames covered by big box 6 mil or 10 mil plastic can work. The downside is that both types of plastic are not designed to hold up to the degradation of sunlight. In short order they are destined for the landfill. Until we can see a market for this oil based product recycling, we think this short term view is hazardous. Of course, in a pinch, ¾” pvc schedule forty, bowed like a hoop house, covered with plastic that saves your crop will be its own blessing
Whether a Lean To or stand alone, having a greenhouse lowers gardening costs. When a south or west facing wall can be used for the 4th wall and much of the structural support, a Lean To greenhouse can be ideal. Here’s why. Often the 4th wall is insulated, and can benefit from solar gain. With a pass through pair of doors at each end, flow through ventilation is available. Or a door on the cool end and an exhaust fan at the hot side. Cover with clear fabric, clear polycarbonate single wall, or double or triple wall that adds a bit of insulation. The opportunities are the same to propagate and nurse your starts. Good place to store that citrus or tow in a pot.
Ornamental Conservatories were the beginning of what could grow when the climate was a bit controllable. They were the rage amongst the wealthy, who initially used them to raise exotic flowers, and other botanicals. One of the best known examples of the master carpentry that went into the grandest conservatory on the West Coast, the San Francisco Conservatory of Flowers. It was recently saved from total decay with a structural makeover that can be read about in Fine Homebuilding.com. The compound curves struck to replace the existing wooden parts was a work of wonder. Today we can find Conservatory Designs and elegant Kits from firms found under conservatories in our search engines.
The oldest glass greenhouse we’re aware of is the wood and glass model the Hanley Sisters had put up for what is known as the Hanley Farm, Or Century Farm. We’re told they had it built before the War. It was the first in all of Jackson County. 1938 or 39 is the date most used. It is still in use today. The original roof was glass as well. Hail damage, rocks by hooligans were all part of the challenge. They persevered and paved the way for propagating starts early enough for our region. Glass greenhouses still exist today. Many are used to raise flowers in the Half Moon Bay, CA area.