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.


14 Responses

  1. Amazing.

  2. People should know that it is easy to do even in an apartment like where we are, there is no odour at all if you do it right (which mean no too much things to do at all except for the first month). We have started our compost bin 3 month ago and it is amazing how many thing can go in even what is no supposed to be “eat” by the worms like cabbage and onion. They do it when there is nothing else. I am now looking to start a second bin with all the worms born in my first bin to compost some coffee from a local shop to get more compost next year and add it to our nice little community garden….

    Don’t be afraid guys just do it you’ll see how it is easy to do.

  3. What is in the gorp from the coffee shop? I understand it to be a “trailmix” of sorts. Do they include the coffee grounds? My rubbermaid bin and I failed terribly this winter. I did discover that springer spaniels will eat worms as they escape across the kitchen floor. *sigh*

  4. Wow – that is huge too! Amazing. We hope to have something setup later this summer, perhaps, since we don’t have much room for a general composter. Looking forward to it.

  5. Thanks everyone.

    Em, the “gorp” is primarily coffee grounds and filters with healthy amounts of lettuce, banana peels, tomatoes, tea bags etc that are the natural waste from a sandwich/smoothie/coffee shop. I tried to get them to put more paper napkins etc in there, but there are limits to how many wrenches I can throw in their operation and still keep it profitable.

    Great encouragement Xavier!

  6. No matter what you do some kids will still be freaked out by worms.

    I have 4 boys and 1 still hates worms no matter how much I get him in the dirt.. Luckily the others make up for him by letting bugs crawl across their faces for fun and things like that.

    I was impressed by your cold cellar worm operation. I didn’t think outdoor bins were possible in WI. We have an indoor one on our To Do List.

  7. thanks Rob, I just check my bin, it seems that I will have to do the second one to recycle only our own waste, cooking from scratch in a veggie/non veggie house produce a lot of things to add to our bin, in the meantime, the big next step is to recycle the cat litter (of course the litter is made of recycled paper). I may try a mix of worm composting and bokashi things, I have to work on that, and take a decision in our next place… moving and living the garden a few weeks before harvesting seems to be an habits for us….

  8. Nice job!

    I am wanting to build one like this in my yard. Could I ask you a few questions?

    * what are you using as a ‘floor’ to the bin? Is it just earth?

    * How is the drainage set up? What is the PVC pipe connected to?

    * Are you able to harvest worm tea with this set up?

    * How many worms can this set up hold?

  9. Thanks Michael!

    The floor of the bin is open to the ground

    The PVC is capped on the uphill end and open on the downhill side. My bin is set in almost pure clay so the ground has no drainage of its own.

    This bin is not set up for tea collection. putting plastic on the bottom may allow this, but you will need to control the amount of water going INTO the system much better than mine to avoid drowning the worms. Another option would be to use a gunny sack full of castings, and soak it in a bucket of water for a day or so to leach out some goodness.

    I have never counted the worms, but somewhere around 20-30#’s (20-30,000) seems like a fair, conservative, estimate. It could be much much more if I spent more time on putting bedding in and watching the PH and moisture content of the system to make it more favorable for the “girls”.

    Good luck!

    • I am so going to do this! But I have a couple of questions:
      1. Do you ever have to “turn” your worm compost?
      2. If I don’t have a floor in my cinder block bin, will the worms escape? Would that be a bad thing?
      3. I’m planning on keeping the worms outside all winter. It sounds like they will be fine as long as I make the bin deep enough. For a mild Kentucky winter, how deep would you recommend?
      Thank you for your help.

  10. […] earlies (Yukon and Kennebec).  I have done one small “hilling” when I added an inch of worm castings a week ago.  Yesterday I added about 3″ of soil to cover the two more vigorous plants and […]

  11. Doris,

    Great! I do *not* turn my compost. As the worms are much more mobile than the bacteria in a compost pile, they can move to the new food as needed. In fact, this is encouraged – I add food from one side of my 3×6′ bin to the other and by the time I am 100% across I can “harvest” castings from the initial side and begin to work my way back. Worm castings are toxic to the worms in higher concentrations – they will eat the food pooping as they go until the food is about done, and then they move on. The bacteria in their castings will finish up the rest of the food. Mixing the pile would mess with this migration.

    The only maintenance I do is to glob a forkful or two of worms into the new food to speed it up. I do not have a floor in mine to help the water drain out and have never had worms escape to the extent that I am at a loss for worms.

    I have kept my worms out for 2 winters now and we hit -15 F both times. My bin is three cinder blocks deep. I suspect I may get near 100% die off of the adult worms, but enough egg casings survive that the colony lives on. I do pile mulch on about 2′ thick to help insulate it. 2-33 runs deep makes for a good sized bin 18″ would be a min that I would recommend.

    Good luck!

    • Thank you so much for your help. I built my worm bin out of cinder blocks. I have it in the corner of my garden. It took me awhile, but I am happy with it. I dug out the dirt and buried the first level of blocks. I put the dug-out dirt in the holes in the cinder blocks. I used the full size standard cinder blocks. I thought that the dirt would be good for insulation in both summer and winter. Then I ordered redworms. I just found out they will not be delivered for another month! If I had known it would take so long, I would have ordered the worms before I even started on the bin. Oh well, maybe a note to anyone new to vermicomposting, check to see when the worms will arrive first!
      My question is this: can I put my kitchen scraps in the bin and let it start decomposing, or will that be bad for the worms when they finally arrive? I hate to throw the scraps that I have been saving for the worms in the garbage. Thanks again.

  12. […] When I compost sod, or other marginal material, it usually isn’t done so it goes into my 30 cu ft outdoor vermi-composter for […]

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