3V Kruschke Greenhouse Dome & More

There are many things to consider after you have finally decided to “pull the trigger” and build your own geodesic greenhouse from scratch. But before you do PLEASE build a model like this one (made from pipe cleaners and drinking straws).

Greenhouse Dome Size

The first of course is how big do you want your biodome to be? This is a function of ability, time, money and space. With unlimited amounts of all these the sky is literally the limit when it comes to the size of your greenhouse dome. However if you are like the rest of us you are severely limited on all or most of these. In which case it is wise to choose a dome a couple sizes smaller than you could afford if you “really stretched”, that way you will have an easier time with the build and have some money left over for greenhouse toys!

Geodesic Frequency

No this isn’t some new WiFi, or satellite radio station. It refers to the number, size and shape of the triangles you will use when you construct your biodome greenhouse. There are advantages and disadvantages of having a 3V, 4V or even a 2V frequency dome. The main two are that lower frequency domes have less struts to manufacture and are simpler to construct. The main disadvantage is that they also are less dome like because long straight struts don’t curve and make that nice “soccer ball” shape we all love.

The advantage of the higher frequency domes is they look fabulous and they use shorter struts so that means less fear when it comes to sourcing your materials. The disadvantage is the huge number of struts and the complexity of assembly.

Kruschke 3V Biodome

This brings us to an alternative option, the Kruschke 3V frequency. This is a slightly different mathematical formula and was developed in cooperation with Bucky Fuller back in the day. It combines some advantages of 4V (having a flat base) and 3V less struts and easier assembly. Here are some spy pics of a Kruschke greenhouse foundation I snapped the other day.

Biodome Basics

Hub system. This is key! Because now that you have decided to build your own backyard dome, you know how big and what frequency the next logical decision is how to connect the struts.

There are many pre-made strut systems, many home brew systems and many geodesic hub systems that just don’t work that well. And to add to the confusion, if you decide to build a Kruschke dome you need odd angled connectors which means you are almost guaranteed to have to do it yourself. You can do compound miter cuts and not use a hub system at all but when you realize how much math and fussy .5 degree accuracy angle cuts you have to make you might just give up.

For those of you making a PVC or conduit pipe geodome this is less of an issue but for those who like the look and feel of wood one needs another option. You can use a PVC pipe as a hub and screw dowels into the ends of your struts, you can try and modify various “off the shelf” systems to work. But what you really need is a simple, no frills, adjustable, forgiving and inexpensive connector system.

Luckily my friend Kacper has one and if I can talk him into letting me “spill the beans” I will do a post about it. If not I know it will be included in his new dome book coming out soon. So don’t give up, there is a solution for those who don’t do compound miter angle cuts but still would like a nice wooden frame for their DIY geodesic greenhouse!

To be continued…

Choosing Biodome Greenhouse Materials

 You’ve done your planning, decided on a location,considered options for foundations.Now it’s time to choose your geodesic greenhouse building material!  Now, If you did not use the below method with your previous building projects, don’t worry – it’s not like its the end of the world! But my suggestion is that you definitely try to employ the following method with any other domes that you build.

The Importance of Choosing Materials Wisely

Just jumping onto the “latest greatest” dome  building material bandwagon without looking at all  the options out there is NOT recommended! The simple fact is there are many options out there for construction of your dome and choosing well can
save you a ton of cash.

So lets look at some options and a few pros and cons of each one.

PVC Pipe

PVC stands for Poly Vinyl Chloride and it is generally used for water piping (irrigation, wells, septic fields, etc.).

Pros: This material is pretty inexpensive, commonly available and easy to work with. You can do the math grab some pipe, make a cutting jig and prep your  pipes with common hand tools. Another advantage is the fact that the pipe ends can actually become the  dome connectors. Commercially available PVC dome connectors are available but, especially for smaller domes not necessary. Resists bugs, rot and moisture.

Cons: High ecological cost. Made using fossil fuel. All plastic type materials have some issues generally due to becoming brittle over time due to extremes of cold or from ultraviolet damage. So if your biodome greenhouse is kept in use (warm) and the pipes are protected from UV this material could be a good choice.

Steel Pipe

Pros: By using galvanized electrical “conduit” piping  available at any big box home improvement store you  have access to a durable, strong and easily worked  material. Resists bugs, rot and mold.  This pipe is available in a number of diameters and comes in ten foot lengths so make sure your design is optimized for maximizing material out of a ten foot pipe. With steel pipe you don’t need dome connectors  because the pipe ends are, drilled and bolted together  thus becoming the dome connectors.

Cons: Medium environmental cost. May have been  recycled but also may have been processed by slave labor in the developing world. Heavy. Can be expensive.  Need specialized tools (hydraulic press) to flatten the  ends prior to drilling. You can do it with a hammer but  it is VERY hard work and easy to screw up. Steel can  rust so painting any areas that have been cut or drilled.

Bamboo

Pros: Light. Renewable resource. VERY green. May be locally available (depending on location and climate). Very strong. Bamboo scaffolding used in Asian countries is often still standing after a hurricane has destroyed the steel building the scaffolding was being used to build! There are some ingenious domes being built using bamboo, either in whole pieces (treated like pipe) or split and almost woven together.

Cons: Can be hard to impossible to find locally. May  be very expensive to buy the required amount. Need specialized skill to build with it. All natural building  materials have “quirks” that can be overcome when you know what you are doing. But if you don’t…. it can get painful. Trust me I speak from experience. Bugs  can eat it. Again proper green treatment will keep  bamboo going strong for longer than we will be around.

Wood

Pros: Wood is almost universally available. There is some kind of wood that can be used for building in  pretty much every place I have ever been. Green and renewable if harvested sustainably. Easy to work with. Lots of infrastructure already in place. Most  people know a carpenter who has tools skills etc. and can be leaned on as a resource. Tools are also readily available at many stores. Durable if done properly. Smells good and is a pleasure to work with!

Cons: Can rot so needs to be treated, luckily there are numerous environmentally sound ways to preserve  wood on the market now. May split, break, or otherwise fail. This can be almost entirely avoided by proper use of tools and by choosing sound wood in the first  place. Bugs can eat it. Again proper green treatment will keep wood solid for generations.

So there you have it. A few ideas of biodome greenhouse  building materials. Look at your needs, your budget and your ecological footprint before you choose your dome building material because once you have 80+ pieces of any material sitting in your garage its a bit late to change to change your mind!

Until next time happy biodome building!

Cold Weather Biodome Greenhouses For Sale or DIY?

The crisp smell of fall is in the air even though summer isn’t quite over yet, and with fall comes cold weather. So, can us North American types keep gardening even when the cold weather hits? The answer is a resounding YES! Of course there is the small matter of locating greenhouses for sale in your area, or ordering a kit or best of all building your own geodesic biodome greenhouse!

So, what’s involved with buying or building a geodome greenhouse and installing it in your backyard? Well, the main thing is planning! Grab all the information you can get, (see Recommended Reading), find a reasonably level area with decent sun exposure and get going.

In many cases if you are building smaller than 100sf then you may not need a building permit, however it is always best to find out before you build in urban or suburban areas. That being said, if you are out in the country there is often much less building code enforcement, however it is always a good idea to use a proven greenhouse dome design to avoid problems later.

Once you have your site picked out, your dome design, (4v, 3v, charter dome, etc.) figured out, and have ordered or prepared your own materials you will usually need some friends to give you a hand with a dome raising party.

Make sure you anchor the base of your dome well! Even though the geodesic shape can withstand incredibly harsh winds there are certainly concerns if you are, for instance, using pvc and greenhouse plastic for your dome. Using cardboard “Sono-tube” forms and “just add water” cement is a simple way to start out when building foundations. Or if you are more industrious you can make a complete ring foundation with insulation outside just don’t forget some pipes through for power and water!

Once you have the foundation level and ready then the fun really begins. Watching a dome come together is amazingly fulfilling because even when partially completed the geodesic shape is very strong and strangely peaceful to be inside.

Once your some frame is complete then you add your covering and north side insulation. For this there are many options including one of my favorites, papercrete! (A mixture of shredded paper sand and portland cement to create insulating cement.) You can then cover your dome with double layer greenhouse plastic, poly-kedar or even glass depending on the size.

Once your dome is up create some beds inside, add water storage on the north side to absorb solar heat during the day and give it off at night. An automatic vent system, min/max thermometer and even aquaponics if you want a complete self sustaining food system. Then when that is done you are ready to plant your cold weather greenhouse crops!

Talk to your local nursery and start out with things that are cold tolerant and then start pushing it as you learn how your particular greenhouse reacts. After you have tastes fresh, organic food you grew yourself you will never go back to imported stuff!

So, if you have been putting off looking for geodome greenhouses for sale, ordering plans online or simply doing it yourself; remember it is much easier than you think and the sooner you start the sooner you will be on your way to food security!