The Benefits of Geodesic Dome Greenhouses
For those of us who grow our own food, the winter months offer a break from gardening, but that also means a break from fresh food. We may have done our fair share of canning and preserving to tide ourselves over, but that doesn’t always make up for the lack of homegrown tomatoes or fresh salads that we grew accustomed to in spring and summer. One solution is to build a greenhouse so we can continue to eat fresh throughout the winter.
There are many types of greenhouses to choose from, but geodesic dome-shaped structures offer many benefits over other styles. Geodesic domes are created by connecting triangles together in a dome shape, using precise angles and measurements.
Geodesic domes earned their spot in the limelight back in the 1940s and 50s when Buckminster Fuller first started playing with them. Fuller was a mathematician, engineer, philosopher, historian, and poet.
He saw the value in geodesic domes and envisioned a future where people lived in domes rather than rectangular homes. Although Fuller’s vision hasn’t come to fruition, we can take his knowledge and use it in our gardens as the same benefits he saw for housing also apply to greenhouses.
Strength of Triangles
The number one benefit of the geodesic dome structure is the strength of the dome. They are much stronger than rectangular buildings and have been known to survive hurricanes, tornadoes, and earthquakes. No internal supports are needed because the triangles distribute weight evenly throughout the structure.
Triangles are the strongest shape there is. This can be seen by nailing four boards together to form a rectangle, and then nailing three boards together to form a triangle. You’ll find that you can easily bend and twist the rectangle, but you won’t be able to make the triangle budge one bit.
Imagine these shapes during an earthquake. Rectangular houses will bend and twist as the ground moves, whereas the triangles that make a dome will remain stable.
Geodesic domes are also impervious to the strongest winds. Because there are no large surface areas for the wind to push against, air just flows around and over the dome. You would expect such a strong building to be heavy and sturdy, but domes are surprisingly light and can even be portable; you can move them around your garden if you don’t install them on a permanent foundation.
If you live in an area that gets a lot of snow in the winter, a geodesic dome greenhouse will make your life easier. Snow builds up on the roof of rectangular greenhouses, but just slides off domes.
Energy Efficient and Cost Effective
Another advantage of geodesic dome greenhouses is their energy efficiency. A building’s heat loss is directly proportionate to the surface area of the building. The dome shape has 30-40 per cent less surface area for the floor space enclosed than a rectangular shape. They also circulate air more efficiently than rectangular structures.
The plants in this type of greenhouse will receive more direct sunlight throughout the day, which means more consistent heat input. A rectangular greenhouse will have less sun in the morning and evening, and the most at midday.
A dome receives consistent sun and heat throughout the day because the sun follows the shape of the dome. Your plants will appreciate this, and the added light and heat will be a benefit during the dark winter months.
Thirty to 40 per cent less surface area also means 30-40 per cent fewer materials used in construction. Geodesic dome greenhouses are relatively inexpensive to construct, depending on the design you use.
You can buy prefab kits that you put together yourself, which are significantly more expensive, or you can do it yourself for only a few hundred dollars. There are online calculators to assist you in finding the precise measurements you need to create the perfect sized dome for your plants.
The do-it-yourself version may require more brain power and physical labor from you, and won’t have all the bells and whistles that a prefab kit has, but it will do the job just fine.
Design Your Dome
If you design your own dome, you will want to consult a good dome calculator to get the proper measurements. You can find multiple dome calculators online. Two that come recommended are desertdomes.com and acidome.ru. The second calculator is in Russian, but it can be translated using an internet translator. Enter your basic requirements for the dome and the calculator will generate the dimensions and angles needed for the struts, and give you a diagram to work from.
There are many material options to choose from when designing your dome greenhouse, such as glass, plastic, steel, or wood. It seems the most affordable route is to use wood and greenhouse plastic. You can create individual triangles, cover them in plastic, and then put them all together, or you can create the entire frame and then cover it with greenhouse plastic.
There are also some bonus add-ons you might want to consider. An automatic window opener is great in any greenhouse. It will automatically open and close a vent or window based on the temperature in the dome. These can be found online. Remember that this is still an indoor environment that you need to control. You need to monitor your temperature just like an indoor growroom.
Another way to maintain the proper temperature is to include thermal mass in your greenhouse. This is as simple as adding an above-ground pond or reservoir. The water in the pond or reservoir will absorb heat during the day and release the heat at night. This is very beneficial during the cold winter months, and it will help maintain a more stable temperature.
Your pond will depend on the size of your greenhouse, but on average, a 600-gallon pond works well for a dome with a radius of eight feet. You could go one step further and install an aquaponics set-up in your greenhouse. This way you grow fish to eat, the fish waste feeds your plants, and their pond acts as thermal mass.
Flooring is another important consideration in any greenhouse. Unless you install a wood or cement floor, you have to defend against burrowing animals who will find their way into your greenhouse looking for a meal. A good way to do this is to layer rodent wire below gravel or whatever else you may use for your foundation.
One final add-on to consider is a pony wall. A pony wall is a short wall that adds one to three feet of height at the base of the dome. This comes in handy if you’d like to add raised beds to the perimeter of your greenhouse, and it gives you more vertical growing space throughout the interior.
If you’d like to grow your food year-round, building a greenhouse is one of the best ways to accomplish your goal. Geodesic dome greenhouses, in particular, have many benefits that rectangular greenhouses do not have. Plus, they make a unique and attractive addition to your garden.