Picture of Geodetic greenhouse (low cost)
Last year I started an allotment and felt the need to build a green house to enjoy the delights of tomatoes and cucumbers. Having built a 30 foot diameter dome before out of steel tubing I thought that there was a good possibility I could make a smaller  dome using some scrap wood I had left over from taking apart some old pallets.

Step 1: Selecting the dimensions

Picture of selecting the dimensions
dome calcs.JPG

Fortunately the Desert domes  http://www.desertdomes.com/ site has a handy calculator to work out the size and type  for any size of dome you need.

I elected to make a 9 foot wide 3 V dome this would stand on a 3 foot high sub frame to give the necessary height I needed.

Desert domes gave me the necessary dimensions for the 3 different length struts.

A=3.13 feet
B=3.63 feet
C=3.7 feet

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Love this project. Just one curiosity question. Is making it out of pvc and clear plastic more expensive or cheaper? I need to consider that I'd have to buy the wood for this project anyway and was curious.

rickharris (author)  elizabethingham13 months ago

Mine was virtually free. So PVC would have made a big hole in my pocket.

cdltpx2 years ago
PLEASE TRY THIS make your rubbers longer where you hook on the bolt go in the hole then around each side of the stick then attach your rubber on the bolt. This should hold the wood in place firmly making your structure very very strong. Also you want to paint your PVC the sun will degrade it. I LOVE DOMES they are what our homes should be made of in this case they can make great homes for the homeless with near throw away PVC pallet wood bolts and innertubes. The cover can be made of TYVEK around the base and windows can be put in with tape. With foild and bubble wrap these can be very warm places to live in.

I'm having trouble visualising this bit with the longer rubbers wrapping around the sticks. Do you have a photo or drawing that can show more clearly what you mean please?

rickharris (author)  cdltpx2 years ago
Thank you for that.
Dr Qui3 years ago
Impressive. I wish my back would improve enough to do something like this. I thing ill start with cold frames on a low wall as I have not yet discovered if I'm a fan of gardening.

How well does the cling film stand up to the elements and the UV sunlight? Ah well at least it will be easy to replace if it does tear.

Its a nice idea to use cling film as you can remove it at the end of the season before the rough weather hits and carries the dome of to Oz, and in spring time you can re wrap and not need to clean a load of glass or perspex panes which is a total pain to do.

Does the cling film have any UV protection, the reason i ask is a friend used that hollow perspex stuff for a green house and it was not as good a success as would be expected, I noticed that my reactions lens did not darken as much as normal and a few areas of expanding foam did not turn brown as they normally do in direct sunlight, I think that the perspex was blocking out to much UV light.
rickharris (author)  Dr Qui3 years ago
Off topic bit i read that Yoga has been shown to help patents with back issues that normal medical processes can't help - tha's assuming

a) your able - ask your Doc

B) a yoga teacher will take you on with a bad back. - should with doc permission.

It's not all about putting your feet behind your head!!! Mostly they help by getting your posture and "core" muscles in the right place and condition.
Amen to that
It a long term problem, I think its coming from injuries I got over 20 years ago, the bill arrived for these about 7 years ago and it took a number of years of tests and various meds that did noting or made it worse to get the diagnosis of fibromyalgia.  by this time i had been working in a hardware store that was in fact making it condition worse as it was cold , drafty was chock full of chemicals that seemed to aggravate things and involved way to much heavy lifting.  By this time I destroyed myself a was just to far gone to recover and handed in my notice when the store changed owners, I was at the stage of the doctor giving me 4 weeks off to recover going back for 4 weeks and again needing 4 weeks off.

I have been watching my posture since seeing a physio a few months ago who pointed out narrowing of the disk at the point where the nerve goes out to the arms and I have been very careful not to aggravate things, I have cut out all heavy lifting in favor of trolleys, I also had to cut out a few people who had the ability to aggravate the condition too.

I recently had to help a friend move house in a hurry and did it knowing I would suffer, but I managed to lock up so bad that the doctor finally gave me a muscle relaxant and with a bit of help from a Homemedics deep muscle massager I have got the thing to a manageable level, I even am starting to see some of the muscle mass I lost in my left arm starting to build again and the cold just don't seem to hit me as hard as before.

So at the moment with ice on the ground I'm actually in a reasonable good order with a little gleam of hope some recovery come the better weather, the secret is not to over do things but its hard to do when you have a s**t load of work that needs doing and has stacked up because I'm not fit to do them.

I even have hope that once we have the winter over us that I may actually start to become much more active and maybe even reach the goal of trying to find some kind of part time work.

rickharris (author)  Dr Qui3 years ago
You have my sympathy! N Ireland isn't the driest and warmest part of the world mind! :-)
lol , tell be about it.!

The new meds are going good at the moment and I have managed to get out in the shed i weather i would have not ventured beyond the front door in so that is a moral booster, I'm looking forward to the oncoming spring as I will get out more
cling film will work for a month before it falls apart
rickharris (author)  Dr Qui3 years ago
The cling film seems to work fine. At least for a season. I dismantled the dome at the end of the year to erect a poly tunnel.

As for the growing no problem tomatoes & cucumbers grew well in there.

I may make another to go over the raised beds I have in the garden. If for no other reason then it attracted a lot of interest when I was building it.

If you have a bad back raised beds and no dig gardening is for you.

Deep composting to avoid digging - talk to your local council parks division they generate more compost than they know what to do with and may be willing to share a lorry load for the asking.

No replacement for a) the cost of home grown and the taste of really fresh produce.

I have a nice little wall that is about as wide as a grow bag and just about the right height to work at while standing. I plan to make a surrounds out of treated fence boards and square tree stakes that will hold a grow bag yet can be made bird and kitty proof.

I will also experiment to see if I can make them snail and slug proof I have a sound theory that I'm going to give a go to see if it works.

I have never been a gardener but I've heard it can become an addiction once started but can be very therapeutic so for that alone I'll give it a shot.
rickharris (author)  Dr Qui3 years ago
Good place to start and not a lot of bending. I suggest getting a potato bag (actually anything that will contain compost will do even stacked old car tires,) and planting 4 or 5 potatoes water well and you will be surprised how many you get in the lat summer.

grow things that are quick - Salad stuff if you like that, Tomatoes give a good return for little more than watering, You will be surprised how many things can be grown in tubs and grow bags. Remember that the grow bag has little nutrient in it after the first 4 or 5 weeks and will need some help with fertilizer, natural or chemical.

My dad is no longer fit to get out into the 2 green houses so I may have a go at growing tomatoes under his instructions, I'm going to try a few salad things and maybe some peas and beans.

We have never grown potatoes before, I guess that after seeing a farmer rent my land and grow 9 acres of spuds that a few little drill looks kind of on the lame side of things.  The land was used for turnips for a number of years (that would have made you tired watching the people working the fields then) but it has been grazed for the last number of years.
JohnS_AU2 years ago
Hi Rick! ... a good job on this dome - I will be starting mine soon :]

Would you tell me what diameter water pipe did you use for the hub and what length did you cut it to fit the 3/4" struts?

rickharris (author)  JohnS_AU2 years ago
The pipe is 2 inch PVC water pipe It is cut at about 1 inch long.

NOTE in the end I had to fit plates over each joint for the reasons given in this instructable:

If your making one I suggest

1. You use thicker struts - 1 inch square of wider.

2. You screw into the end of the struts through the PVC pipe.

OR you cut notches in the pipe o hold the bands in place.

3. As an alternative you could use cut lengths of hose pipe pushed onto the struts and bolted through the middle to make the join.

Although this allows you to assemble the ome as you can see the rubber bands tend to move round the pipe as there is noting to stop them.

triumphman3 years ago
I see this site has become a place to share your medical, physical and personal problems. Some people just have to do that. They are in need of others to say, Oh, I'm sorry and feel bad too. Well, that is the freedom of Democracy, we are all thankful for that. We are lucky to be able to express ourselves openly, unlike many, who are suppressed in other countries. Well, get well soon, and keep us all informed of your progress!
rickharris (author)  edvannatta3 years ago
Hello, Thanks I am pleased you enjoyed the instructable. You can build these domes VERY big ( !00's of feet high) BUT bigger costs more. You would also need to use a stronger covering material PVC for example.
lotusduck3 years ago
That should be sort of sturdy, but rubber does degrade under heat and sun, and that would probably be your first point of failure in the whole construction.
rickharris (author)  lotusduck3 years ago
Rubber does degenerate under UV light BUT - Carbon filled rubber such as a tyre inner tube is intended to last longer, AND as you may note I did in fact change the design to include a more permanent method of joining using ply panels.

manuka3 years ago
Very elegant indeed Rick ! I've built quite a few domes & greenhouses myself over the decades, but find New Zealand's high UV levels & wind soon ruin thin plastic cladding. That + finger poking kids,scratching cats & -argh!- the odd "smoker's corner cigarette burn thru's ... As a trial some time back I took to using 1mm VIVAK® PETG (Polyethylene Terephthalate Glycol) nailed to wooden trellis, & have found this technique far superior-the plastic sheets become almost invisible too. Structures are very long lasting ( >10 years) & additionally look very elegant. Perhaps best of all they can be readily customised to fit into obscure garden corners too! See my approach  =>http://www.instructables.com/id/Trellis-greenhouse
rickharris (author)  manuka3 years ago
Good idea - Fortunately I didn't have any of those issues UV being an almost unknown form of radiation here!!

I have looked at getting a dome shrink wrapped. Although the film is opaque it lets through a considerable amount of light and there have been efforts to use it on poly tunnels.

Cost is of course an issue hence the cling film. I did look at cutting 2 ltr PET bottles up into window panes but unfortunately this would have require smaller triangles and I didn't have enough wood freely available at the time. - back to cling film.

How is the Picaxe world??
Very cool! I was just looking at a site called TurtleTuffShelters.com that makes kits that can be shelters or greenhouses.
I don't need one this year, but next year! - that's another story.

Thank you for this instructable! Very very cool. I'm also going to forward it to my SIL, who may need another greenhouse in the near future. This would be right up her alley.

I looked at their site - They are somewhat expensive (1200 USD for the frame 3590 for a finished product) in the general way of things - The frame of a 24 foot dia dome will cost less than 400USD perhaps £200 the cover depends on what you use. BUT here in the UK I can buy PVC sheet 11 mtr x 9 mtr for £75 this was the cover for our poly tunnel.

The frame does not need to be made from aluminium steel tube is cheaper and a coat of paint stops rust. These things are not as they are long term dwellings and lightness is irrelevent as you have to build on site in situ anyway with something that big.

I agree completely. I was just commenting that I happened upon their site. Not that I was considering purchasing. I just found it ironic that your instructable showed up the same day I looked at them. I could never afford that anyway - but yours - that is possible!
Fate! :-) happy building - make the struts at least 1 inch square and save a lot of bother. Then you can screw them through the PVC rings to keep things square and ridged as well as the rubber bands.
Thanks - Kits tend to be expensive with a little work you can slash the costs.
mikeasaurus3 years ago
I almost can't believe that the connection points and the membrane lasted so long, great job. I like the low-cost approach!
rickharris (author)  mikeasaurus3 years ago
It worked well for the time I needed it - The only reason it didn't get remade bigger was we already had a frame suitable for a Poly tunnel
rickharris (author)  mikeasaurus3 years ago
Desert domes will do the calculating for you. BUT they are all from hemispherical domes.

HOWEVER you can use as much of the dome as you like so by starting from a higher ring you get a lower dome you just need to work out how wide you need to enter in the calculator to get the dome width you need.

IF you looking at a more permanent structure I would strongly recommend you use 19mm (3/4 inch) steel tubing and flatten the ends and bolt together (see desert domes site) - It's not as costly as you might think.

I built a 30 foot diameter dome out of this tube and it was strong enough for me to climb over - I weigh 200 pounds.

For a more permanent cover approach a company who shrink wrap boats. they can wrap the structure in a drum tight skin that will last a long time and they heat seal it all together.

This is a UK based example.

Domes are used for all sorts of coverings and this example below is for an event dome from a UK company Gala tents  cost is about $12000 BUt you could build for a fraction of that cost.

Lindie3 years ago
Great job! Thanks for sharing.
rickharris (author)  Lindie3 years ago
Welcome Thanks.
rwlh19503 years ago
Very imaginative, I particularly like the way you used bike inner tube as a jointing method. And clingfilm. Wonderful stuff
rickharris (author)  rwlh19503 years ago
hgilman3 years ago
i built one 2 years ago with thin bamboo for the sticks and for this part i bought a 6 dollar hose. then i just cut the whole hose into 5 inch sections. for the 6 pointed stars i took 3, 5 inch sections and drilled a hole through them and put a bolt through the 3 holes. then i screwed each point to one bamboo. for the 5 pointed stars i just connected 2, 5 inch sections and one 3 inch section with a bolt and nut
rickharris (author)  hgilman3 years ago
Yep I did that as well as a trial to get some idea of how big it should be. I almost used it but thought it wasn't going to be strong enough to stand up to wind.

Good idea though.
akoray3 years ago
good idea rubber band conection alsoplaywood
I am planing to produce ball pit for preschools
kcheatle3 years ago
This is awesome- we actually already have a steel geodesic climbing gym for the kids to play on in the backyard- and my neighbor has a similar one built of PVC. Depending upon when the kids are ready to play on it again- I could see moving the dome to a section of our yard, planting an early garden, and once the weather warms up enough for them to want to play again- unwrapping and moving the dome back... hmmm...
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