The covering of the geodome greenhouse makes all the difference on how much protection you will have. A single layer of greenhouse plastic poly keeps a greenhouse around 4 degrees warmer at night than the outside temperature.
Adding another layer of plastic filled with air in between the two would more than double the protection. Also, double-walled polycarbonate panels would significantly increase the protection. Depending on how much protection you want, get creative with the cover.
Because of the shape of the dome, covering it can get tricky. The Acidome calculator calculates nicely the size of the facets, which is especially important for pricier coverings.
Covering the GeoDome Greenhouse with greenhouse plastic film
We covered our first dome with used greenhouse plastic poly that was given to us by a friend. It still had plenty of life left. It was a commercial greenhouse, and the greenhouse plastic was of good quality. 9 years later that dome is still covered with the same plastic!
With our free plastic cover, we simply laid the struts on the plastic and cut the 2-3 facets approximately. Cutting the plastic for 3 facets in a row worked the best. Any overlaps we trimmed with a utility knife.
Make sure the upper facets overlap the lower ones to keep the rainwater out of the greenhouse. Just the same way shingles are done.
We stapled the plastic to the struts and then used 1 cm planks to hold it in place which also pointed out the structure of the Geodesic Dome even more. We like it :).
Covering the GeoDome Greenhouse with Shrink Film
It was fairly easy to pull it over, however, the shrinking was not so easy. But that wasn’t the biggest problem.
The foil when shrunk looses some of its optical transparency. It becomes slightly opaque. In a greenhouse, however, we want all the light we can have.
So we gave up on shrinking the foil and folded the overlaps and stapled the plastic to the struts and then used 1 cm planks to hold it in place as we did with our first dome. It only lasted 3 summers and bursted during a cold period in the winter.
We would not recommend covering a greenhouse with shrink film.
Cold climate challenge
Living in a climate where temperature can drop to -40 degrees the covering has to withstand extreme cold often in combination with some wind.
Since the structure of the dome secures the covering between the wooden struts, it contracts more when it gets colder. With a bit of wind on a freezing night, it becomes almost brittle. The advantage though is that only the affected areas can be patched, without having to cover the whole dome.
Covering the GeoDome Greenhouse with polycarbonate panels
Polycarbonate panels are probably the most durable cover you can have. You can choose the thickness you want and the size of the panels you need. If growing a year-round garden in the geodesic dome is your goal, this would be a great covering to choose.
Here is a great tutorial about how to cover a GeoDome Greenhouse with polycarbonate panels.
If you want to build a Geodesic Dome too, we share a step by step How to build a GeoDome Greenhouse.