One of the projects we will be starting this fall is a greenhouse. When we first started researching greenhouses, I thought it would be a simple straight forward plan. We just needed to figure out where on the property to build it, right? I was very wrong. There are many options for a greenhouse and, as I have come to learn, a greenhouse can be so much more than I thought.
There’s an ancient Persian proverb that says, “When you understand how to do a thing, the doing is easy; if you find it difficult, you do not understand it.” “There are of course numerous homestead activities where a basic understanding can make the difference, between making a thing simple or difficult and between a gratifying success or disheartening failure. Nowhere on the homestead is this dichotomy more evident than when one attempts to modify plant environment by the use of a forcing structure.” I read that quote while I was buried in greenhouse research and though it extremely fitting for our current predicament.
We have narrowed our choices down to four different types of greenhouses.Attached Greenhouse or a Lean-to – A lean-to greenhouse is a half greenhouse, split along the peak of the roof, or ridge line. This greenhouse would be attached to our barn. There are a lot of advantages to this type; it conserves space, less greenhouse material cost, easy access to water and electricity and ease of construction. Some cons for this type are that it will need to be heated for year round gardening, and sun exposure will be more limited than with a free standing structure.Traditional Freestanding Structures – Freestanding greenhouses are separate structures; they can be set apart from other buildings for more sun exposure and can be made as large or small as desired. This greenhouse will be a prefab kit. The pros include easy assembly, low cost, and the ability to move it if we really needed to. A big con for this option is that year round gardening will not be possible with the kit that we are able to afford.Geodesic Dome Greenhouse – This type of greenhouse has a dome shape which makes good use of small spaces. This structure uses the minimum materials for construction and gives maximum usable space. This type of greenhouse is very energy efficient. Cons include material cost and the need for heat to garden year-round.Pit Greenhouse or Walipini – A Pit greenhouse is exactly what it sounds like, a 6-8 foot deep pit with a greenhouse top. A pit greenhouse makes use of the naturally stable temperature and heat-sink capacity of the soil to keep greenhouse temperature stable. The environment will be 20 degrees warmer than the outside low temperature without supplemental heat. The pit greenhouse would give us the ability to grow food year round without additional heat and has the least construction cost of all the options. Cons for this type of greenhouse are all in the logistics, there is a lot of math and planning involved in digging the pit and installing drainage.
A little greenhouse research reveals the fact that, although George Washington and Thomas Jefferson both had greenhouses, the oldest reported greenhouse in the U.S. was not a greenhouse as we know it today. It was, rather, a pit covered with glass on the south side, and earth insulation on the north. This pit greenhouse was built into the side of a Waltham, Massachusetts hill around1800. Although this seems like the most radical options, it is in fact quite traditional outside of US garden circles.
Out of the four options, we are leaning towards the lean-to greenhouse. We will do a long post on the greenhouse when we build it. What would your dream greenhouse be?