In the planning stages of building our house here we had always thought we would eventually build a greenhouse. At our former location in Wellington we had a small, non-heated greenhouse, which provided us with cold-tolerant things like spinach, kale, chard, lettuce and beet greens throughout most of the winter. It also provided a place to finish and harden the seedlings I had started under lights indoors. It was attached to the south side of our house, under our deck, so the north side of the greenhouse was protected by the house. (See photos of this one below.) It was a great addition to the garden there, so we planned to do it again.
We mulled over whether to attach it to the house or build a free-standing greenhouse. Here are some of the pros & cons:
Attached to the house:
- Water and electricity readily available
- North side protected by house
- Easily accessible in winter
Free-Standing:
- More available space for a larger greenhouse
- More available light for the plants
- Would be farther from the house; less accessible
- Water and electricity would be more of a challenge
- Would require insulation, particularly on the north wall

We chose to attach the greenhouse to the house, under our deck on the south faces. (I say “face-s” because with a 14-sided house, we used two of the sections.) We also decided we would like some sort of heat source, to allow for more growing throughout the winter. While thinking through the options, Tim decided we could have radiant heat in the floor, with a solar collector to provide that heat as well as enough capacity to provide hot water for the house.

The greenhouse is now complete! It is full of beautiful, growing vegetables. Tim is now working to complete the solar collector and the system for heating. The solar collector is standing to the left of the greenhouse in the photo above. Inside the crawlspace, at the back of the greenhouse, is the mechanical room, which houses the water collection tank and controls. Tim is in the process of writing a detailed document of how the greenhouse was built, which will be included when complete.

Since the greenhouse is attached to the house, water and electricity are readily available. The glazing is 5-wall polycarbonate, about 5/8″ thick. It includes approximately 100 square feet of raised bed space 28″ deep, radiant in-floor heating, concrete floor to maintain thermal mass, a pond filled with about 200 gallons of water for thermal mass. Eventually we may remove the lid and put fish and/or water plants in the pond, perhaps a waterfall, but that’s a “someday” project. There is also a lighted grow-bench area for starting seedlings.
Venting is provided by two large ceiling vents equipped with automatic openers, in addition to the door which may remain open as needed. We have installed an oscillating wall fan to help with airflow.

For our first winter, Tim devised a way to put down insulation over the glazing at night to keep the cold out and the warmth inside. After the time-consuming efforts of installing them nightly and removing them each morning, we decided it was not worth the effort. We still put up the insulation on the sides (see
photo) and leave them there day and night throughout the winter. It doesn’t restrict the light all that much during the day, and provides some extra warmth, particularly when it is windy.
Tim has created a detailed document describing all the “nuts and bolts” of how the greenhouse was made and why we did what we did. It does need to be updated with a few recent changes but can be viewed HERE.
UPDATE NOVEMBER 2019
Since our first successful winters with the greenhouse, we have since made some improvements to the heating system. The concrete floor, the soil and the pond (which holds about 200 gallons of water) all provide thermal mass storage. When the greenhouse was planned and built, we installed radiant in-floor heating, to be heated with water from our solar collector. Over time, we determined that this was not necessary. The concrete floor and the soil beds stay plenty warm without the in-floor heat, but what needs more warmth overnight and on the coldest days is the air. This past year Tim purchased and installed a used wall heater which uses the hot water from our solar collector as its heat source. This has worked quite well to keep the greenhouse warm overnight most nights, and we have an electric space heater to add additional warmth on the coldest of nights, when it has been too cloudy to heat enough water with the sun. Tim has these all set on with thermostat sensors and computer programs that turn everything on and off as needed. Good to have a geeky guy around! We also no longer put up the insulation over the glazing each night, which was labor-intensive and not all that helpful.
BONUS!
As an additional source of heating, we have a unique situation. The greenhouse is built on the south side of our home, and includes a door to our crawlspace. Most of the crawlspace is backfilled with dirt, and the temperature remains quite even–not too hot, not to cool. Tim has added a duct (see at top of photo above) with a fan to blow the hot air from the greenhouse into the crawlspace during the day which warms up the crawlspace a bit. At night, the door to this crawlspace is left open, so the warm air stored there can circulate back into the greenhouse for added warmth. In the summer, by keeping the door to the crawlspace open the coolness from the crawlspace helps keep the greenhouse cooler. Just an added benefit of attaching the greenhouse to the house!
Here are photos of our former greenhouse, which served us well, but our new greenhouse is 10x better!







In general, almost everything took longer to reach maturity than expected. For instance, I picked the very first, 55-day tomato on day 74. I finally harvested the “100 day” onions, even though they could have had more growth, on about day 150 and later. Since the tops never really fell over on their own, they’re not curing properly, and they won’t last long in storage. Many other things took a lot longer than expected as well. I will detail those along with my observation of each vegetable family.













At least, we haven’t seen evidence of them burrowing through it. Our second line of defense against these guys will be a layer of stucco netting, which is a LOT cheaper than the hardware cloth which is often recommended as protection from ground squirrels. Any long roots should still be able to penetrate both the stucco netting and the rocky bottom. Additionally, just to the inside of the perimeter beds, there will be a layer of plastic lining the walkway, to keep both the weeds and the squirrels out.
This is a shot of the garden site, the morning of April 19, 2017. Although we have 40 acres, most of which is pretty flat with no trees, we are placing the garden here, in a protected spot from wind, and where plants may get a little shade in the afternoons. The area gets full sun from the E-SE all morning into early afternoon. We feel this site will be best, to protect them from the full effect of the intense sun at our elevation. It is also relatively close to the water hydrant. Tim has begun clearing the area and is building the raised beds. The garden itself will be 41 x 35 feet in size, a little over 1400 square feet. The actual planting bed space will be 740 square feet. There is some slope on this site, so it will be terraced a bit along that slope. The entrance to the garden will be wide enough for the tractor to fit through, which has been and will continue to be a big help. The beds will be filled with a soil combination of natural soil, well-aged horse manure, used duck bedding, some additional organic matter and compost.
In addition to planning the physical garden, Tim has put together a potting bench area and grow lights under the house in our crawl space. It’s not real pretty down there, but functional. The sink and potting area are helpful for me to mix and prepare the soil blocks I use to start seedlings. Under these lights, I already have started several things; mostly greens for the cold frame section which will be planted mid-May, onions and a few other things which take a long time to get started. The lights can be raised as the plants grow. If necessary, we have more lights that can be placed on the lower side of this bench. (See more about my soil block approach 

After functioning quite well with our temporary kitchen, we’re finally getting around to making the custom kitchen that we have envisioned for so long. Before that could begin, however, I had to get my workshop in good working order. This included adding heat so I could work regardless of the weather, purchasing some vitally needed tools for making the cabinets (yes, they really were necessary) and spending some time implementing good dust collection. There is a lot of sawdust generated in woodworking and now is not the time to ignore good health and safety practices. So, now that the shop is in pretty good shape … let the cabinet making begin!





Here’s where the garden will go. This photo was taken 


