Posts Tagged ‘geodome’

Greenhouse grow dome

Sunday, July 23rd, 2017

Why would anyone need a greenhouse in Portugal? Given adequate water and soil fertility, the climate provides more or less ideal growing conditions pretty much year round. General climatic conditions though are one thing. Specific microclimates are another. This quinta has mountain ridges to the south and west and doesn’t get much heat from the sun early in the year. As a result, the clay soils are slow to warm in Spring. Any summer vegetable planted out much before May tends to stand still and then take a while to get going again once soil temperatures rise, so peppers and aubergines frequently don’t get harvested until October and November. A greenhouse in the sunniest spot on the quinta would make a huge difference. I could grow plants from seed in early Spring, bring them on while the soils warm up, and overwinter those which can be effectively perennialised for an early start the following Spring.

I also wanted to experiment with aquaponics to find a way of growing vegetables intensively without the need for supplemental irrigation.

The completion of the geodesic dome greenhouse was consequently eagerly anticipated. The covers went on at the end of April. Seeds were sown and plantings made. And since then, I’ve been revising my ideas of how growing our food here can be achieved almost as fast as the plants themselves have been growing.

Geodesic dome greenhouse covers installed, end of April 2017

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Geodome greenhouse progress

Monday, May 22nd, 2017

Projects here seem to have their own timing. What seem like frustrating delays at the time have an uncanny knack of turning out to be necessary pauses: intervals which allow for much better solutions to emerge. The geodome greenhouse has been no exception. With the groundwork complete by the middle of last summer, I was hoping to have it covered in time for winter. This wasn’t to be. My fault mostly. I wasn’t happy with the lack of solid UV resistance data and guarantees on clear PVC and went off to ferret out something more robust. Several lengthy explorations into such materials as ETFE and polycarbonate later, it was clear that robust was beyond budget-busting, so in the end I came full circle back to the PVC.

But during the delay, two things happened. One of the suppliers we were in contact with listed a new high transparency UV-treated PVC film. And Liam acquired a high-frequency PVC welder. I’m sure neither of these facts will mean much to many, but take it from me: the end result is just so much better than it would have been had neither of those two things happened.

The greenhouse cover is now almost complete!

The PVC cover goes onto the geodome greenhouse

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Subterranean heating & cooling system

Wednesday, May 11th, 2016

The previous post on the geodesic dome greenhouse outlined the logic in choosing a dome for this site and how it was by far the better option for fitting in all the things I wanted to have in this greenhouse. These include an aquaponics system and a bathroom as well as growing space for tropical and frost-tender fruits and vegetables, seed growing areas, a rocket-stove water heater and a worm farm – a fair bit to cram into an area measuring just 7x5m at the outset.

Geodesic dome greenhouse frame

I also wanted to build in a subterranean heating & cooling system (SHCS) to make even better use of all the thermal mass present in the solid bedrock floor and back wall. This is a proven low-tech solution for maintaining comfortable temperatures and humidity levels in the greenhouse year round. It can minimise or even eliminate the need for supplementary heating or cooling.

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Geodesic dome greenhouse

Sunday, May 8th, 2016

Back in July 2012 we dug a chunk out of the mountainside in preparation for a ferrocement rainwater harvesting tank. Plans for the tank were later shelved due to budget constraints, but a good use for the site was never in doubt. It’s one of the few parts of the quinta to have sun at winter solstice, so was perfect for a greenhouse.

Geodesic dome greenhouse site

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