Make your own food growdome from the plans in this book.
All in all the wood, screws, plastic sheet, sand and cement cost me around £150 for this greenhouse, a great investment for a growdome which is now into its sixth year with only minor repairs in re-taping the seams .
Ever since learning about Buckminster Fuller at art college I have been fascinated by icosahedral structures. They are quite simple structures but once completed, very stable. Over a few years I have enjoyed the opportunity to experiment with some useful structures to make growing domes for food.
Dome 1: I always want to include as much found, upcycled or recycled material in my constructions as I can. The first dome was made from thirty hazel sticks gathered from the woods over a winter, whist walking my dog, and a length of polytunnel liner. The first growdome cost about £30, shown below. What I learned from this one was that growing spaces need a good airflow and that if you are going to strim around them, they need to be raised from the ground otherwise the strimmer will cut the lining. Also, one very important point – if you don’t anchor them down than they will simply blow away. This one lifted from the ground and flew for 30 feet, turning a complete somersault and landing the right way up, scattering all my seedlings over the ground. The dome was completely unharmed which gives you some idea as to the resilience of this structure.
Dome 2: My second growdome used bamboo sticks and I connected them with bits of old hosepipe nailed together into six-pointed star shapes. It had many more connections and elongated itself. This had a good ventilation system, in fact so good that the blackbird family soon learnt how to get in and steal my strawberries, until I netted them out. The dome lasted for a couple of seasons and was made from recycled plastic sheets, bubble wrap that came through the post and cling-film for less than £20, which was mainly the cost of the bamboo.
The joints for this dome were too flexible and it gradually turned into an egg shape under its own weight. I shored the roof up for a season with a seven foot high ‘strawberry tower’, made of strawberry pots of diminishing size, stacked on each other. The problem with this structure was that it was just too complicated – such a small structure didn’t need so many rods and connectors. The great thing about this dome though, was that it was built on some old, concrete garage walls as the base which just worked so well for solar passive heat sink.
Dome 3: I chose to go for a much stronger and permanent structure and ordered tannelised, two-by-one wood especially for the purpose, along with sand and cement to put in a ‘crazy paving’ base from my garden of rocks (on the edge of Bodmin Moor).
This structure is the top half of a a two-frequency icosahedron. I can’t over-emphasise the importance of having a model to work to for dome building that has more than one strut length, otherwise it is easy to get lost in the structure. I include ‘model making of domes in the book so that you can gain an entry level knowledge of geodesic dome making. Marking the different strut lengths helps in the full-scale construction so I painted mine with some left-over wood treatment paint. I connected the struts using metal discs, pre-cut with shears and drilled using a cardboard template. These were made from a sheet of corrugated galvanized roofing that seemed to have been flattened by a tractor. Once you get the hang of them, these geodesic structures can be used for all sorts of things!
Connecting the struts and raising the dome up on tyres allowed me to connect new pieces to the underside. I had to give special attention to the joints at the top because they took additional strain during the construction. I bolted plywood disks on for support. Piece by piece, it took shape and it became clear to me that a half-sphere dome would be easily tall enough rather than the five eighths dome I had intended to build. This was fine as it meant there was wood leftover for an inside structure.
Then the floor went in, like a mini patio made from all the flattish rocks and bits of slate I could get my hands on. I painted some of the rocks at the back black, and left them raised to absorb more heat from the sun.
Finally, it was time to put on the polytunnel cover. I ordered another £30 worth because I intended to also recycle the cover from the first dome into this one. For the glazing part I cut the sheeting into rough triangles, stapled it onto the struts and then trimmed to size. It is best to work from the bottom up, then the rain will flow down, and not into, the dome due to the overlaps.
I made one top triangle as a detachable window from a broken umbrella. This helped with the top glazing and is essential for airflow. I also made a detachable window on one side for wheelbarrow access. All the overlaps were then sealed using a waterproof tape made for polytunnels. I made a door by taking out a cross strut and putting in bent hazel sticks which pushed the space open so as not to weaken the structure. This has a porch from which I hang netting to keep out the ever-present blackbirds who are always welcome in my garden because of their beautiful songs.
The first season I had a good crop of blueberries, picking salad, coriander absolutely loved the warmth in there, squashes, tomatoes, basil and peppers. Since I have grown marrows, courgettes, tomatoes, cucamelons, stevia, more pepper varieties, melons, a lemon tree, avocados and cucamelons to mention a few!
I am often in there tending my food and have even put in a sink and draining board with an internal water supply from rain water butts. The dome is now in its sixth year and the only maintenance it has required is a re-taping of the seams.
‘The DIY Growdome‘ is available in both digital and paperback versions on the links below. It contains detailed information on how to make all three domes and a special tribute to Buckminster Fuller, a genius of the 20th Century.
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