The dome has fascinated me for a long time. Like some arched cathedrals in the Middle Ages, they provide large open spaces without central support members to interfere with movement within the structure. They also provide less wind resistance than other structures, which is a benefit of SLV.

For many years, I have been watching Pamela Rose and her former partner Rodney Volkmar install many different sizes of domes in various environments around Crestone, so when I want to learn more about growing in domes, I called Pamela. Although she no longer sells or builds them, she agreed to let me visit her domes and show me the features that she believes make them a good environment for growth throughout the year. 

The dome is based on Buckminster Fuller’s design work. According to Wikipedia, “A geodesic dome is a hemispherical thin shell structure based on a geodesic polyhedron. The triangular elements of the dome are structurally rigid and stress the structure Distributed throughout the structure, enabling the geodesic dome to withstand very heavy loads." 

Pamela said Udgar Parsons developed the design for the greenhouse. The company where she works now has a new owner. Lem Tingley now owns the original Growing Sand of Pagosa Springs. An extensive website www.comingspaces.com provides examples of various sizes of domes and how to use them.

Sold as a kit, the greenhouse must be assembled on site, and Pamela still occasionally helps with this process. The dome is set up and connected to a 24-inch column wall, standing on a concrete slab or footer, or on the ground. The dome part of the kit has a structural frame made of wooden triangles, and a glass window made of 5-wall polycarbonate, which is cut into triangular panels and fixed with tape around the edges. The triangular panels are fixed to wood and fixed together with a patented metal plate to form a center for the intersection of 5 or 6 triangles.  

Pamela’s 18-foot dome has three panels that open the ventilation when the internal temperature is too high, and close when the external cools down. They work automatically and are controlled by a small cylinder filled with beeswax. As the temperature rises, the beeswax expands and opens the panel, then shrinks and closes the panel as the air cools. The two panels on both sides of the dome and the third panel at the top allow hot air to escape. A small solar fan helps air circulation and keeps the dome warm or cool in summer.  

Several other functions help to regulate the internal temperature. On the north side of the dome, the inside of the panel is covered with a foil back insulating film, which can absorb sunlight and reflect it back to the dome in winter. Below this area is a pond used as a radiator, and the surrounding foil transfers heat into the water. It absorbs heat during the day and releases heat at night. During this process, the 4-inch plastic pipe is behind the pond, then under the growth bed, and then the surface on the south side, and the solar fan helps the air pass through the system. All this helps to make the system an average of 20° higher than the outdoor temperature in winter. The insulated entrance door has a small spire, called a snow shed, to prevent snow and rain from entering.

The planting bed surrounds the inner circumference of the wall. They are two feet deep and about three feet wide. Although most domes have beds on the walls, the inner bed located in the center of the dome can be arranged according to the needs of the gardener. In this case, Pamela has another bed near the pond. In the pond, several goldfish swim among the water plants to help control algae and mosquito larvae. A small solar pump circulates the water, and the fish get a little fish food every day. 

Pamela says she can grow hardy vegetables throughout the winter. In February, she started using some space to start planting seeds outdoors in spring and summer. In summer, she usually grows hot weather crops such as tomatoes, peppers and eggplant indoors. I saw that some tomato vines from last year were eight to ten feet long.

The growing dome comes in many sizes. The smallest diameter is 15 feet, and it is recommended for 2 to 3 people. The biggest, at 42' is a community. I have seen some of various sizes in our community, most of which are used to grow plants, but there is a larger one that is used as an indoor family play area in winter. Growing Domes offers various upgrades to the infrastructure, including things like solar loft fans and solar waterfalls, both of which are suitable for larger models.

Pamela has been working with these domes for about 20 years and stated that some maintenance will be required over time. For example, polycarbonate panels need to be retaped after about 10 to 12 years, while polycarbonate will turn slightly yellow after about 15 to 20 years. Over time, the fan may need to be repaired or replaced, and other components may need maintenance. However, she feels that it is very maintenance-free because many of its systems are designed to use passive solar energy.

Although this growing system has some real advantages over the other systems I discussed in previous articles, it was initially more costly. Growing Spaces lists the current prices of some domes as follows: 

18', for 3 to 4 people, 255 square feet, 10'-8” high, 45 USD/square foot, 11,950 USD. 

33', for 8 to 9 people, 855 square feet, 15'-5 inches high, 32 dollars per square foot, 28,350 dollars.

Although these prices may be reasonable on average over time, the initial investment may become an obstacle for some gardeners. However, from an aesthetic and practical point of view, Growing Domes may be a satisfactory choice.

Crestone Eagle is a monthly newspaper/magazine serving Crestone, Saguache County and North St. Louis Valley.

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