Big Az Worm Bin

Even though I live in an HOA, I am able to keep a livestock herd of about 250,000 strong right in my backyard, and you’d never know it. See I dig vermicomposting. 3 years ago we tried the Rubbermaid Bin in the basement like the Worm Woman taught us. But I am a lazy gardener (energetic builder, yes, but lazy in the gardening!) and we didn’t keep enough litter in it so it attracted flies. So I moved them outside, and made the bin MUCH bigger, as is my wont. The bin we built last year is 3×5′ and 2 feet deep. That works out to about a cu yard of vermicompost at peak capacity. It also means I have a crap load of worms in there. This weekend a remodel of our composting system meant that I needed to move our worm bin, so I thought I’d take the time to post a pictorial of our bin. As you can see in the first shot, the bin is made of half width cinder block. I bury the bin 2.5 block deep for insulation in all seasons, but I loose stack the blocks so that the bin can drain, and also to make it semi portable (I seem to redeisgn things every 1-2 years as I learn more, so I don’t like to make things too permanent. to hold the blocks together I pound 1.5″ stakes into them, but really with soil on the outside, and worm turds on the inside they aren’t really going anywhere. Our winters are fierce, so I bury the bin in about 2 feet of leaves from the city municipal yard, and then in the spring use it in my compost bins and to mulch the gardens.

I mostly feed my worms the gorp buckets I get from the Coffee Shop, which also means that my vermicompost is full of tomato seeds. The second shot shows gorp that is about 75% vermicompost. It is also very wet since I had to take all the worms and vermicompost out of their old bin, stage them in piles and wheelbarrows (yes I have more than one) and the barrows filled up with rain despite their covers. This shot also shows a better perspective on how freakishly large the bin is. That is 10 cu ft of worm sludge and the bin is not even half full!

If you think this is alot of effort for some worm poop you’d be right. But after the first time I top dressed with vermicompost I became an absolute believer in its power to add Deep Fertility to plants. Our roses have never bloomed like they did the year they got vermicompost, and it is still my favorite side dressing for heavy feeders like tomatoes. I don’t really understand it myself, but I have seen studies that have actually shown that worm “casts” or manure actually has higher fertility than the things they eat. Seems like alchemy to me, but I have seen enough results to be a believer.  The trick is similar to how yeast makes wheat more nutritious for us.  Take a pound of wheat berries, chew them up and even if you don’t break your teeth, you won’t get too much protein or carbs from them.  Why?  Those nutrients are tied up in a form we can’t digest.  Now, grind up the wheat into flour, add some water and fungus (yeast) and the fungus will convert the nutrients into forms our digestive tracks can process.  Worms do the same for organic matter – their casts are full of microbes and other microbes that continue to break down the remaining organic matter – in this way their are more nutrients, or more precisely nutrients in a more available form, for plants to use.  But its still magic to watch 20#’s of gorp turn into soil every week!

The final picture shows the completed bin. I made a simple 2-piece lid out of cedar decking. Raccoons and Opposums would love to eat your worms, so covering them with something substantial is important. Also, in the final shot you can see the two pieces of perforated PVC that I inserted next to the cinder blocks for drainage. The last bin was surrounded on all sides by soil for insulation, but our “soil” is virtually all clay so the bin itself would fill up with water almost to the top, NOT a good situation for worms!! 1 10′ chunk cut in half should do the trick.

This past summer I finally found a decent way to harvest my worm castings without taking out all the worms. In years past I have tried to divide the bin in half with welded wire, and put fresh food in one side to draw the worms over. That works, but it also means that you are wasting half your bin space. I have also just scooped out a barrow ful (abot 1/5th a bin), worms and all and spread it. There are more than enough worms left to repopulate (they double in population every 4-6 weeks in ideal environments), but I felt bad about sacrificing 50,000 of my buddies.

But Growing Power, which vermicomposts on an industrial scale, taught me a super simple way. Take a sheet of aluminum window screen and lay it over the finished vermicompost and then lay fresh food stuffs on top of that and cover it with a sheet of canvas or something. In a few weeks the worms will have squeezed through the mesh to eat the fresh food, and you can pull up the screen and transfer them to a new bin, or a cleaned out old one. Slick!

Vermicomposting is also great with kids. I HATE to see little uns that are afraid of worms, and trust me, if you start them young enough they simple LOVE to grub around in the worm bin searching for their “friends”!

Be the Change.

-Rob

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