Backyard Aquaponics
A place to discuss aquaponics

I am embarking on a project to design and build, from the ground up, based on my prior experience doing small scale Aquaponics in IBCs and a lot of hydroponics. The plan is starting from nothing to build a greenhouse for an Aquaponics system and then install that greenhouse and the systems on my .28 acre lot (of which most of it is in the back yard). I wanted to use this thread as sort of a log of this adventure and to bounce ideas off the considerable experience of this forum.

Right now we have chosen the site and size for the greenhouse which puts us right at the legal limit of what we can do on our property. We have .28 acres in the Austin area but we had to dismantle most of our hydroponic and Aquaponic stuff when we moved from colorado last year. It is accumulating dust in my garage at the moment. We have a large back yard but I have to say grass annoys me. It can't be eaten and requires hordes of water and care. So time to replace it with a large greenhouse. It will be 40' x 15' and sit right at the back corner of our lot.

And so begins the design:



This is the left elevation of what will ultimately be a passive solar greenhouse. The concrete block wall will be on the north side and the curve will have polycarbonate panels. There are two knee walls, one on the lower left that will have inlet vents running the length of the greenhouse every other stud, the other is high up on the north wall. The difference in height will promote the stack effect (http://chuck-wright.com/calculators/stack_effect.html) which will cause the greenhouse to pull a flow through the bottom vents and exit the top vents with no electricity or moving parts. The bigger the openings, height and temperature differential, the higher the flow. With this design and 20square feet of vent with 5 degree temperature differential the flow should be roughly 2043 cfm. You could increase the effectiveness of the flow by drawing air through vents underground (thermal mass cooling) or through evaporative cooling pads (though you will slow the air flow a bit with the pads).

The floor will be made of compacted road base with 1 inch of sand and dry set flagstone with polymeric sand. The main structure of the greenhouse will be 2x4 cedar studs that have been covered with a layer of fiberglass and epoxy after they have been cut to shape. This should make them last longer than I will on the planet. The north wall will be concrete block wall reinforced with rebar. Here is where i come to my first points of internal debate:

1) I could put the door on the north wall but then you will have to walk behind the greenhouse to get in. It would be easier to build and light but more annoying to enter.
2) The concrete block wall will be 12 feet above ground. I am not sure if I will need buttresses of some kind to increase its overall stability. I really need to find an engineer that knows his way around concrete.

Anyway .. more to come soon. All comments and input are welcome.

Hi Kraythe,

Your greenhouse design looks great! I can tell you're really thinking it through construction wise, which is awesome. Per your questions:

1. I know that I've never seen one with a door in the back, though I can't see why it would be a problem. I'm guessing putting the door closest to your house or where you park would make you happiest long term.

2. You have to get an engineer to look at block walls of a certain height. What height depends on if it's a retaining wall (yours isn't) and how tall it is. I know that a lot depends on soil type. I suspect buttressing with some kind of angled piece would be wise. You'll probably need some kind of structure to support your glazing anyhow.

If you put a bit of furring behind the block wall and added some insulation behind it, you could store a lot of heat in the concrete. Not sure if you'd need that.

Have you visited Rob Nash in Austin? http://www.austinaquaponics.com/