Okay, I’m making some plans for the new Backyard Crop.
First, last year my crop yield was terrible. Plants died in the heat, there was no place to start plants, and the ants…. those ants got EVERYWHERE.
It’s obviously too late to start a crop this year, and my fishery and my wood shop are a disaster. So I’ve decided that my aquaponics grow beds are going to be inside – in their own greenhouse.
Fresno has some funny laws about hoop houses and anything made with pipes and “tarps”. But they are fine with greenhouses, and anything that looks like a shed. It can be pretty large. So after a little research, I thought I’d build a Stimson-style bow-roof greenhouse. These things are pretty tough once all the pieces are installed. They look something like this (image is just a general mockup – not a true blueprint).
Stimson, the inventor of this version of a gothic building, is a shipwright who found a way to make very inexpensive ribs for the structure that are extremely strong. Large versions of this greenhouse have easily gone though 70 mph hurricane force winds.
Did I mention it was inexpensive? The ribs and structure for my shed should cost less than $400 tops, and may be less than $250. The plastic sheeting for the shed will cost more.
I’m planning on a 12 foot by 25 foot greenhouse, on top of a partly buried sump which will be used to feed the fish tanks and the grow beds. The grow beds will be in the greenhouse, and the fish tanks will be in a covered shed.
The plan is to have a wall of growbeds on one side of the greenhouse, and a line of individually watered aquaponics pots on the other wall. The greenhouse structure is physically very strong, so I will be able to hang grow towers for strawberries along the main ridge beam.
The most difficult part of building this structure will be in creating the form to turn out the 22~28 supports that I’ll be making. Wood is important too… I’ll try it first with dimensional lumber ripped to the appropriate thickness, but I’m learning that much of that warps. I might have to use something different than pine.
Another big problem I’m running into is one of running out of water in the sump. If all the growbeds fill at once, and if my sump isn’t large enough, then the pump runs dry and starts to self-destruct. Affnan’s bell syphons could allow the system to sychronize, and if my sump isn’t large enough…. bam! No more expensive pump.
So I started looking at the cheap 3/4 inch water valves that go on yard sprinkler systems. They need a low voltage to turn them on or off. Two hooked into an XOR configuration, with one controlling input to a grow bed and one controlling the output would fill a grow bed and then at a command allow it to drain. One command, two devices.
Plus, my pump delivers lots of water pressure – so I could also use these same electric valves on the grow towers and to the pots, using Rainbird style drip sprinklers.
This also fits with my long term plans to monitor water quality so I can figure out how my fish are doing.
So to make this all happen, I recently ordered a Raspberry Pi computer, and have been taking the online training course in Python at the Codeacademy website. (Just a note, if you are familiar with programming in C, then Python won’t be very difficult for you.)
As you can see, I’ve got the Raspberry Pi online, and am running Rasbian Linux – and I’m actually surfing the net through my WIFI adapter! The computer is everything inside that little red box. Everything else, monitor, keyboard, mouse…. they are plugged in through HDMI and USB.
The idea is to create a WIFI computer in the fish shed that will monitor water quality and log it to a database online where I will be able to see at a glance what everything is doing. I hope to see trends, graphs, charts… everything. It may not happen very soon – I’m still building structure.
Will I get a harvest next year? I don’t know. It’s too soon to tell if I will get everything done before planting season starts. And it starts pretty soon!
But I own this house now – so there’s always 2015.
Update: 12 July 2013:
I’ve updated the image of the Stimson Bow Roof greenhouse to show what I’m planning. The greenhouse is 8 feet 5 inches wide, 24 feet, 3 inches long, and 10 feet high. It will have a raised plywood floor on 4×4 runners. There will be room for fans on one end, and louvers on the other. I changed the width to fit my yard better (I really don’t need it to be 12 feet wide either).
I haven’t calculated the cost yet, but I will post it when I get it.