Vol 3, No 1       

dome greenhouse

The Year-Round
Dome Greenhouse

with Udgar Parsons

by Wynn Free
When Buckminster Fuller invented the geodesic dome in the late 1940s, he was convinced it would revolutionize construction — but he was wrong. Even though domes offer many advantages — including efficiency, strength, and economy — the post-and-beam box prevails.

But one area in which geodesic domes have really succeeded is as greenhouses.

The closed-ecosystem greenhouse

Not long ago, closed-system greenhouse domes were available to the public, geared at enabling their owners to create totally sustainable, year-round agricultural units. These domes produced not only vegetables but also fish — enough of both to meet several families' needs for food.

In a closed-system "biodome," plants convert the sun's energy to food and flowers, which attract insects that feed the fish. Fertilizer from the fish in turn nourishes the roots of the vegetables and flowers.

The dome shape, along with the presence of water, affords the greenhouse gardener a more-or-less habitable temperature year-'round, even in wintry climates. Theoretically, then, these contrivances should have been able to continue indefinitely, feeding themselves and producing crops.

Eden Malaysian Rainforest biomeBut it didn't happen that way. In order to create a closed system, the dome had to be very large, and so the structures were extremely expensive. Even more troubling, it was found that artificially-created closed systems may suddenly — for no apparent reason — die overnight, everywhere and all at once. Today, closed-system biodomes exist only in the context of large-scale endeavors, like Windstar — and the Eden Project.

Cornwall's Eden Project

The Eden Project is a closed-system biodome project that continues and flourishes. Located in Cornwall, England, it consists of a series of huge domes that were built at a cost of $110 million and have been billed by some as the Eighth Wonder of the World.

Calling itself "a gateway into the world of plants and people," the Eden Project aims to show how sustainable development depends on plants.

Aside from supporting a myriad of ongoing scientific ecological research projects, Eden also is open to the public, with attendance at theme-park levels — exceeding all expectations.

Eden has three "biomes," each devoted to plants of a different climate. The domes that make up these biomes are of extremely lightweight construction. In fact, the humid "tropics" biome weighs less than the air inside it.

Thousands of plants from around the world have been planted in the biomes.

The backyard gardening dome

dome greenhouseIf you want to grow your own food even in adverse climates, and you have some room in your backyard, a smaller, consumer-model dome greenhouse may be your method of choice.

Although they're not closed eco-systems, fifteen-foot dome greenhouses can be made quite cheaply from scratch or, for about $4000, from a kit that comes complete with water-cistern-cum-fishtank and multiclimate operating instructions. A structure of this size can grow enough vegetables to supply two to three people (depending upon how much they like vegetables) on a year-'round basis. That seems like a pretty timely idea.

To find out about dome greenhouses, we talked with Udgar Parsons, owner of Growing Spaces in Pagosa Springs, Colorado. His company specializes in the manufacture of dome kits for greenhouse use.

Wynn: What inspired you to start a dome business for greenhouses?

Udgar: I was involved with the Windstar Foundation, founded by John Denver, back in 1986, and we had a large greenhouse called a biodome. It was a terrific structure, very inspirational, a five-eighths sphere fifty feet in diameter. It was growing on three levels, and could grow plants all year 'round without extra heat, even in the Rocky Mountains.

I was totally inspired by this structure. But unfortunately it cost eighty thousand dollars to build, and so was not affordable by the average person. But I thought I could make a structure that did the same thing for about two thousand dollars. So that's what I did.

Wynn: How big was that one?

Udgar: It was fifteen feet in diameter. I called it a Growing Dome. Since then, I've developed five different sizes, from fifteen feet up to forty-two feet in diameter. And they will grow all winter long, with little or no extra heating or cooling. That's the amazing thing.

Wynn: With inflation, what does a fifteen-footer cost these days?

Udgar: It's now four thousand dollars, but it's much better than the older one that cost only two thousand. It's got many more features, and it's much more long-lasting.

Wynn: I would guess that one group of people interested in this type of product would be survivalists. Is that true?

Udgar: Well, not so many now. Back in the Y2K days we had an article in Survival magazine, and we got lots of response. But now, because so much of our food is full of pesticides and may be genetically modified, it seems that more people are interested in growing their own food for health reasons. People want organic food, and they've decided the way to do this is to grow it themslves. So today it's more about health than survival.

Wynn: How many people could a fifteen-foot dome supply with food?

cukes, parsley, chard and marigolds in a domeUdgar: They did lots of measurements with the Windstar Dome, and found that they could grow three pounds of food per square foot per year. So a fifteen-footer can grow four hundred to five hundred pounds in a year. Supposedly, the average person eats about 200 pounds of vegetables per year, so that's enough for two or three people, depending upon how many vegetables they eat.

Wynn: Can you grow everything in the greenhouse that you find in the stores? Carrots, broccoli, cauliflower. . .?

Udgar: Yes. People have even experimented with growing fruits like limes, lemons, figs, grapes, and berries. So it's not just vegetables, but fruit. And also, of course, flowers — just for the enjoyment.

Basically, in a climate like Colorado where we get nights that go down to zero degrees, we have two climates in the dome: summer and winter. Winter is when we grow our frost- and cold-hearty plants: the cabbage family, the onion family, kale, broccoli, Brussels sprouts, collards, leeks, garlic, peas, lettuce, all of the chard family, spinach, beets. . . all those are frost hearty, and they love the dome in the winter because it's cool. Even with sub-zero temperatures outside of the dome, the inside will go just a couple of degrees below freezing. And as soon as the sun comes out, the plants just start growing again. And that's without a heater.

In the summer, you have a whole different scenario, because now you have the heat-loving plants: tomatoes, squash, peppers, zucchini, cantaloupe, melon, okra — they all love the heat.

The dome actually stays much cooler than a conventional greenhouse, where you'd usually have an overheating situation unless you spent lots of money on coolers. But the dome manages to grow the heat loving-plants in the summer because it has more thermal stability than a normal greenhouse.

Wynn: So, in other words, the dome is warmer in the winter, and cooler in the summer than a regular greenhouse?

Udgar: Yes, and that is because it has a huge water tank that provides thermal mass, or thermal stability.

Wynn: How big is the tank?

Udgar: The tank for an average-size dome would hold a thousand gallons of water, and it would sit on the north side of the dome wall, underneath the north wall insulation. This positioning regulates the temperature, and you can use the water container as a wonderful pond for fish and aquatic plants. That's a nice feature. With or without the fish, it's the water tank in our domes that causes them to significantly outperform regular greenhouses.

Wynn: Did Buckminster Fuller ever use domes as greenhouses?

Udgar: In the early days at Windstar, just before I got there, he was involved in helping them design their geometry for the first biodome. So yes, he was involved in the process.

Wynn: At Windstar, did John Denver have much hands-on involvement?

Udgar: No, he was more the inspiration. He provided the finances and the name behind it. He put together the inspiration for people to look at the idea of bio-sustainability on our planet. That was his function.

Wynn: How fragile is a dome greenhouse's growing environment?

Udgar: The environment in a dome is very healthful. Generally, if you give plants adequate water and healthy soil, they will survive.

I had this dome in Alaska — a gentleman had built it one October and then left for California. There was no one taking care of it, but in the spring, when he returned, he found the biggest dandelions he'd ever seen in his whole life inside that dome!

Wynn: So from your experience things growing inside a dome are more hearty?

Udgar: Plants are at least as hearty as things grown in a greenhouse or outside, and probably more so. The plants love it in the dome, it's like a jungle, you have to fight your way in there. I can go away for a week with my automatic watering system set to go on every couple of days, and when I get back it's really amazing.

Wynn: How about efficiency of water usage?

Udgar: Domes use about one-fourth the water that regular outdoor growing methods require for the same amount of production.

Wynn: Does the dome focus energy, like pyramids do?

Udgar: I personally don't have any experience to comment on that, but we get reports from our users that they sense a high energy in the dome environment. Some people sit in their domes and meditate for hours.

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