In our early twenties, fresh out of the city with two small children and another on the way, my husband and I purchased a tiny house. It was a 700 square foot “cottage,” because when things are tight, you can call it a “cottage” and it somehow makes it seem more romantic. It was in the wetlands of Virginia Beach and was an “as is” charmer of a home. One of its more sturdy, well-built features was its 10 x 12′ back deck.
Our first summer there, we enjoyed the deck a few times, and it was an excellent location, right off the kitchen. However, we realized that it just got too hot to enjoy it much in the summer, until the sun went down. And by then, the mosquitoes would be so thick that no one in their right mind would hang out there unless they had an insect screen or a deathwish.
Then, when I read of attached greenhouses in some country-living type magazine, I was intrigued. The southern exposure we had was ample in that location, and it would give us a place to start all our garden vegetables and plants in the early Spring. Within a few weeks time of reading the article, we were able to secure a cache of storm windows complete with screens second-hand, and we realized we now would also have an outdoor “room” for summer without sacrificing ourselves on the altar of biting insects.
The first roof we had on the attached greenhouse was of corrugated plastic; it was clear, allowed ample light and heat to enter the house on even the colder-but-sunny days, as long as the sky was clear, and the temperature was above freezing.
This meant that on days where I’d ordinarily have to stoke up the woodstove to get us warm (or turn on the very expensive, dusty baseboard heaters) I could instead just open the back door into the a world of greenery and warmth. Within a half-hour or so, the entire house would be just as well-heated by virtue of the sun.
We were so impressed with this “free” heat that the sun shared even on the chilingest of days that a couple of years later we knocked down the shed next to the greenhouse that covered the other half of the southern wall. Here, we installed a large set of glass doors in the girls’ south-facing bedroom.
Where before they’d had a wall and one small window that they had to stand on their beds to look out of before, they now had a beautiful view of the back gardens and could access the backyard via a small deck with a grapevine-covered pergola. Some people expressed that our kids would “escape,” but with such a nice view, there was now nothing to “escape” from.
Adding glass doors on the south end was such an inexpensive but drastic change; for less than $200, we purchased the doors second-hand, along with some framing to reinforce the wall and a gallon of paint. We had transformed their admittedly former dreary little room into an extension of the garden. On sunny days, the house now heated itself quite well, within about fifteen minutes as opposed to thirty, and it was cozy and warm. Plus, we now had one more escape route if there were a house fire, which is always a consideration when one heats their home with a wood stove.
So impressed were we with the dynamics of an attached greenhouse that it was always in our plans for our next home, in Scottsville. It just took a little while to get around to it.
Our biggest considerations for the space at our present location were: size, materials, and not blocking the already-present passive solar attributes of the house, achieved by lots of glazing on its South side.
We knew we wanted a larger greenhouse than our previous one, which was 10 x 12′. We settled on double that, because our kids were older and we knew we’d need to grow more starts for us and small nursery business. The depth from the back door of twelve feet was decided by observing several winter solstices and the amount of heat gain we wanted from the project.
Of course, the greenhouse is on the south of the house. It would make no sense to build one anywhere else, facing any other direction. Free-standing greenhouses should still be aligned East-West, with their widest side to the South. Though they are standard in commercial operations, they are still doubly (at least) as hard to keep evenly heated in colder temperatures because they may not be buffered from North winds like an attached greenhouse naturally does.
We found this out when our friend built a quarter-hoop greenhouse at our place in Virginia Beach after we’d built the attached one I previously described. At 12 x 30′, it was ample-size, but aside from having to walk 75 feet out to it, it got cold easily…even though it was insulated with foam panels, and a buffer of small trees and grapevines set twelve feet from its back, with nothing shading its East or South sides. Sure, we had tomatoes in January, but generally only if we used a plug-in heater. Our electricity cost didn’t go up much, and we probably ate more than ten dollars’ worth of fresh tomatoes (the cost for the additional electricity) but clearly, the system was not as sustainable as if we’d used the space attached to our house.
The reason I think attached greenhouses are just not as widespread in use as they should be is that you are unlikely to see them in commercial applications. Seeing their use commercially popularizes the general concept of greenhouses, even if they are not widely constructed in more optimal locations. However, for anyone with a space on the south wall of a building and the desire to the garden beyond their regular growing season, this type of set-up makes good sense.
With good planning, even if you do not intend to grow and sell plants, the amount you could save on heat could pay for the space in as little as one to three years.
Our second attached greenhouse, which we built in Scottsville at Horseshoe Hill, began as an insulated, poured concrete pad, accomplished with some tools borrowed from Michael’s place of work (i.e. the whacker packer…what a name for a tool!) and help from our local Barter network. We moved some of the gravel originally in our barn house up to the spot to delineate a few years before, gradually compacting the area, and finally poured cement there.
The day of the actual pour was very exciting. Several people showed up (unlike when we poured the floor for our house back in September 2001) and several brought bread or cookies (thanks, Marca-Maria and Olivia!) There was a moment of panic when we realized the form walls were buckling, but quick thinking and shoring up minimized any concrete casualties (the first of which would have been a hillside garden getting unintentional paving).
By the end of the day, we had a very smooth concrete pad with a drain for the center of the floor (Thanks, Gary and Alec!) We (I) were ridiculously happy that January day, spraying the water and watching it go down toward the appropriated hole, as gravity and planning dictated. The same wonderful, predictable result every time.
We were able to get some left-over timbers from our friend Alec’s new timber frame house, and he sold us very nice windows that he’d decided not to use in that same building. They are double-paned and crank open and actually nicer than what is in our actual house!
Throughout the summer, Michael and I worked on the space, first covering the framing with plastic to use for Spring herb and vegetable starts and heating the house. We were able to make back most of the materials’ investment in plant sales, and we decided to put a shingled roof on it, making it more a “sunspace” than a technical “greenhouse.” Thank you to David and Jennifer for helping with that! I think they were happy to learn how to put on shingles since they were also planning to build a cabin in their backyard and were going to be doing a similar-style roof.
Our aforementioned friend Gary, along with Woody and Giovanni helped with the windows and considered which way I wanted them to open with regard to the direction of the prevailing winds. Again, thank you all!
Our greenhouse, it must be noted, may appear to be more like a sunroom, because it now has a roof. However, Mark Freeman, in his book on greenhouses, points out that space with an insulated roof attached to the south of a building will capture and contain that heat better than a clear, non-insulated roof (like we had before) that will allow more of that heat to escape. So, any solar gain you miss on sunnier days in the winter would have been mostly lost in the evening any how. And depending upon your latitude, the summer sun will also be kept out by this same roof , which is a double benefit. So I want to be re-iterate that glass or clear roofs on attached greenhouses are wholly unnecessary in Virginia, at least.
The shade created in the summer by the insulated roof makes an ideal place to dry herbs, or keep perennial starts somewhat shaded (reducing the water needed for them till they are planted).
In the winter, the greenhouse space makes an ideal place to over-winter hardy annuals like Cole crops, perennials and water or house plants. Mostly I am looking forward to using the warm space (with awesome floor drainage!!!) for paper-making in the Winter, now that the long wide tables are free of most plants, and I will not be kept busy seeding, watering, planting, weeding, harvesting and marketing those same said plants. (written in 2007, Ed.) It will be nice to exercise creativity of a different but equally important kind until the growing season’s whirlwind begins again.
J arranges flowers in the early morning light of the greenhouse.