Boulder Vermicomposting

Worm Weight Calculator

I built an online calculator to let you figure out how the weight of worms you have in your bin by separating out just a fraction of them.  It’s the same method I outlined here, when I found that I have approximately 7 lbs of worms in my bin.  But now the calculator does all the work.

Check it out.

Add comment July 28th, 2009

Vermicomposting Horse Manure

Via the Manure Management articles section of the Equine Extension department of Colorado State University, I found this interesting article on vermicomposting horse manure.  It references another article about composting horse manure quite a bit.

These articles are quite explicit about methods to create the compost, and have good information about the processes of vermicomposting or composting.  They also do a good job of explaining some of the decisions a someone with horse manure will need to take (what kind of worms, how to set up windrows).

Here’s a great quote about the profligacy of E. foetida:

50 pounds of Eisenia will reproduce to 1,000 pounds of worms shortly after four doubling
periods (in just over 16 months). In two years, that initial 50 pounds of Eisenia will be more than enough (3200 pounds) to vermicompost the manure from 30 horses.

And the article also answers a very important question about horse dewormers and redworms:

Will horse dewormers kill red worms?

The most common wormer used is known by the brand name Ivermectin® made by the Merial Company. Merial’s research shows that the active chemicals in Ivermectin® are deactivated when manure is exposed to sunlight. Equine studies show that 95 percent of the active chemicals in Ivermectin® are deactivated in the horse before being passed in the feces. Leading experts in vermicomposting believe that the concentration of Ivermectin® in the horse manure is not high enough to seriously injure Eisenia.

Apparently the Ivermectin used for horses has been rebranded Zimecterin; it might be worth asking the vet about this situation because I couldn’t find anything.

These articles don’t, however, give much advice about what to do with the presumably vast amount of vermicompost your worms will be generating.  Assuming the worms reduce the weight of the manure by 20%, that’s still over 4 tons of vermicompost a week when your operation is fully going (assuming 30 horses).  This is about all the advice you get on what to do with castings:

Castings can be tilled into the soil directly from the windrow or screened for adding to greenhouse soil mixes, potted plants, lawns, and gardens.

Vermicomposting at this scale is an economic decision.  50 pounds of red wrigglers will probably cost you 500-700 bucks, and you have labor, land and equipment costs.  On the other hand, you have to get rid of your manure somehow and beyond castings, you might be able to start a business selling redworms to home wormkeepers like me.

5 comments July 18th, 2009

EPA promoting vermicomposting

The EPA (USA’s Environmental Protection Agency) has a great starter page about worm composting, with links to some pretty good information sources:

Through this method, red worms—not nightcrawlers or field worms found in gardens— are placed in bins with organic matter in order to break it down into a high-value compost called castings. Worm bins are easy to construct (they are also commercially available) and can be adapted to accommodate the volume of food scraps generated.

It’s more of a ‘what is vermicomposting’ than it is ‘how do I start’, but I love the fact that the US federal government (as well as some local governments) promotes vermicomposting.

Add comment July 8th, 2009

Durango Compost Company

Via the Durango Telegraph, I found this story about the Durango Compost Co, which details the genesis and progress of the Durango Compost Co, founded by Jennifer Craig.  This company is built around vermicomposting:

[Durango Composting Company] offers three main services: household composters and worms; public education; and commercial use and consulting. The Composting Co.’s most visible presence is at the Farmers Market, where Craig sells 35-gallon buckets of compost for $35; “compost tea,” a compost-steeped liquid used as fertilizer and to prevent plant disease; and the “Can-O-Worms” home worm composters. In addition, Craig also gives presentations at local schools and works with businesses, such as Ska Brewing and Cyprus Café, interested in worm composting.

The key to the company’s founding was the partnership with a coffee shop: “[Durango Coffee Company owner Tim Wheeler] would pay Craig to take his grounds off his hands. In exchange, he would get a cut of the profits from the final garden-ready product.”

I love to see business models around vermicomposting operations, as I believe they’re key to making the process really sustainable in the long term. I found no website for the Durango Compost Company and I was unable to find a telephone number, but the contact info for the coffee company is here.

6 comments July 2nd, 2009