Polyculture

Lepomis microlophus, aka shellcracker or redear sunfish
I gave a call to my nearest commercial fishery (90 minutes away...) and he extolled the benefits of catfish and shellcracker. Seems shellcracker is a type of sunfish, like blue gill, but they grow faster and larger. Theyre called shellcracker because they like to munch on aquatic snails, cracking the shells in their powerful back jaws.

Most of what I can find on shellcracker (or redear sunfish) is on sport fishing or pond culture websites. I can find all kinds of recommendations for stocking density for a 1-2 acre pond, for example. And much of that literature explains the mix of fishes you want to get. Carolina Fish Hatchery goes so far as to offer pond stocking packages. For example, the package for a new 1 acre pond would run $765 and consists of:

700 Bluegill (2-4")
300 Shellcracker (2-4")
10# Minnows
100 Largemouth Bass (4-6")
100 Channel Catfish (6-8")

I told the nice man at the local fishery how excited I was to visit once Id set up my system. He proceeded to tell me about the Fish Wagon. Fish Wagon is a family owned pond stocking business out of Arkansas that delivers to customers at local agricultural supply stores during the warmer months. Im sure the nice man at the fishery 90 minutes from my house wouldnt mind my business, but he thought local delivery of fish that didnt cost me shipping might work better for me.

I thought that was right nice of him.

If Im looking at a polyculture of fish, I dont mind going for a 300 gallon tank. Even though Ive read on the internet somewhere that you can have as many as 3 bluefish per gallon of water (900 blue gill), I think Id settle for a tiny fraction of the numbers cited above.

Heres the way the Rubbermaid 300 gallon fish tank and 50 (or 100) gallon grow beds could fit in the 8x18 space:



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In other news, my tilapia have yet to ship. Theyre coming from near Kansas City, which has been hit by a big winter storm. Looking forward to having them in hand sometime next week!

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Poor Mans Greenhouse aka High Tunnel

$50 Greenhouse at doorgarden.com

One of my early rants focused on the fact that it gets cold up here in the continental US. And not everyone has a greenhouse.

But with the White House using hoop houses and the USDA running around helping folks construct high tunnels, Ive been seeing a lot about how one might be able to do a greenhouse for far less than $$$. The idea is you bend PVC pipe between anchors at either edge of the area, then drape the hoops with 6 mil polyethylene. Done.

Some things to consider.

Structural Stability


Door Garden reports the structure sprang back to shape once the snow was removed. But there are various ideas for making the initial structure stronger.

1. Go Gothic - theres a reason those northern barbarians didnt use the classic roman arch - because it was liable to fail under load (think snow). A pointy arch can do beautiful things. Check out the post Another snow day at tinyfarmblog.com.
   
   
2. Use metal conduit rather than PVC. Turns out a conduit bender can be had for less than $40, and metal conduit is about the same price as PVC. Check out the Chiots Run post about Building Hoop Houses out of Electrical Conduit.

Size constraints

• Tiny yard. I live in a townhome. The entire thing is only 20 wide and about as deep.
  
  
• Covenants. Im not allowed to build anything that is taller than the fence around my yard.

Im thinking of using the metal conduit to achieve a slightly more complex shape that would give me enough space for two rows of aquaponic growbeds without being taller than 6 feet. Here are some initial sketches:




The tall, flat wall will be next to the northern side of my fenced area. For the 8 x 15 plan shown, the conduit, bender, and 6 mil sheeting will run me about $250 (prices at Home Depot as of 2/21/11). Add a door, some lumber, and chicken wire, and were around $300. Id do a CHOP2 configuration, so there will be ~200-250 gallons of water in the system even though the tank, itself, is only 150 gallons. The Rubbermaid growbeds are $130 for the 150 gallon tank and $70 for each 50 gallon growbed and sump tank, so those would run me $700. Total $1000.

But Id have no cost for grow-lights and the electricity needed to run them. Thatd be sweet.

Too bad I cant use tilapia outdoors. Ill have to figure out what fish could do OK outside. Goldfish always work - theyre cheap and dirty, perfect for aquaponics. But ornamental goldfish can be carcinogenic if theyve ever been treated with Malachite Green, so we couldnt eat them. Ill give my buddy at the Virginia Department of Game and Inland Fisheries a holler and find out what he recommends.

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