The Crestone Eagle • June, 2021
Garden Guru: Pamela’s ‘Growing Spaces’ dome
by Matie Belle Lakish
Domes have fascinated me for a long time. Like some of the arched cathedrals of medieval times, they offer large open spaces without central support members to interfere with movement within the structure. They also offer less wind resistance than other structures, a benefit in the SLV.
For years, I watched as Pamela Rose and her former partner, Rodney Volkmar, installed many domes of various sizes in a variety of settings around Crestone, so when I wanted more information about growing in a dome, I called Pamela. Although she is no longer selling or constructing them, she agreed to give me a tour of her dome and show me the features that she feels makes them a good environment for year-round growing.
The domes are based on the design work of Buckminster Fuller, and 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 distribute the structural stress throughout the structure, making geodesic domes able to withstand very heavy loads for their size.”
Pamela says that Udgar Parsons developed the design used for the greenhouses. The company that she worked for now has new owners. Lem Tingley now owns the original Growing Sand in Pagosa Springs. An extensive website, www.growingspaces.com, gives examples of the various sizes of domes and ways in which they have been used.
Sold as a kit, the greenhouse must be assembled on-site, and Pamela still occasionally helps with this process. The dome is set on, and attached to, a 24” stem wall that sets on a concrete slab or footer, or on the ground. The dome part of the kit has a structural framework made of wooden triangles, and a glazing of 5-wall polycarbonate cut into triangular panels framed and taped around the edges. The triangular panels are attached to the wood and held together with a patented metal plate that forms a hub for the intersection of 5 or 6 triangles.
Pamela’s 18’ dome has three panels that open for ventilation when temperatures inside get too warm, and close as it cools outside. They work automatically, and are controlled by a small cylinder filled with beeswax. As temperatures warm, the beeswax expands and opens the panel, then contracts and closes it as the air cools. Two panels on the sides of the dome, and the third at the top, let hot air escape. A small solar-powered fan assists in circulating the air, as well as keeping the dome warm, or cool in summer.
Several other features help to moderate the temperature inside. On the north side of the dome, the panels are covered on the inside with a foil-backed insulated film that catches the sunlight in winter and reflects it back into the dome. Below this area is a pond which acts as a heat-sink, and the foil around it directs heat into the water. It absorbs heat during the day and releases it at night. It is aided in this process by 4” plastic tubing that goes behind the pond, then under the growing beds, and then surfaces on the south side, where the solar fan helps move air through the system. This all serves to keep the system 20° above the outside temperature, on average, in the winter. An insulated entry door has a small peaked roof, called a snowshed, to keep snow and rain from entering.
Growing beds circle the inner perimeter of the walls. They are two feet deep and about three feet wide. While most domes have beds along the walls, the inner bed, in the center of the dome, can be arranged to fit the gardener’s needs. In this case, Pamela has another bed that abuts the pond. In the pond, several goldfish swim among water plants, and help keep algae and mosquito larvae under control. A small solar pump circulates the water, and the fish get a little fish food every day.
Pamela says that she is able to grow hardy greens throughout the winter. In February, she begins using some space to start seeds for spring and summer planting outdoors. She typically plants hot weather crops like tomatoes, peppers and eggplants inside during the summer. I saw some of last year’s tomato vines that were eight or ten feet long.
Growing Domes come in a variety of sizes. The smallest one is 15’ in diameter and is suggested to feed 2 to 3 people. The largest, at 42’ is slated for a community. I have seen some of all sizes within our community, with most used for growing plants, but one larger one is used as an indoor family play area in winter. Growing Domes offers a variety of upgrades to the basics, including such things as a Solar Attic Fan and a Solar-Powered Waterfall, both available for the larger models.
Pamela has been working with these domes for about 20 years, and said that some maintenance is needed over time. For instance, the polycarbonate panels will need to be re-taped after about 10 to 12 years, and the polycarbonate tends to yellow somewhat after about 15 to 20 years. Fans may need to be repaired or replaced over time, and other components may need maintenance. However, she feels it is remarkably maintenance free, as so many of its systems are designed to work with passive solar.
While this growing system has some real advantages over the others I have discussed in previous articles, it is more costly, initially. Growing Spaces lists their current prices for some domes as follows:
18’, feeding 3 to 4 people, 255 sq. ft. 10’-8” high, $45/ sq. ft. for $11,950.
33’, feeding 8 to 9 people, 855 sq. ft. 15’-5” in. high, $32/ sq. ft. for $28,350.
While these prices may be reasonable if averaged out over time, the initial investment may be an impediment for some gardeners. However, from an esthetic and practical point of view, the Growing Domes may be a satisfying choice.