Sunday, July 13, 2008

Update on my vermiculture experiment

Earlier this year, I decided to purchase a Pet Poo Converter and some red worms, and compost my two cats' poop. My experiment started in March 2008 and I finally decided to harvest the worm castings in my compost unit. It looked dark, rich and nothing like the shredded newspaper with which I started. Since many sites I consulted when starting noted concerns about using cat poo in composting, I decided to refrain from using the worm compost in edibles and limit its use to my landscaping plants. I have plans for edible landscaping, but most of the items currently planted in my yard are for decorative, wildlife or shading purposes.

In particular, one of my trees, my mountain ash, was late in leafing out this spring and has not yet bloomed like its counterparts have. While many web sites advise against fertilizing trees, I decided to add compost around the tree since it is not the same as adding a powdered fertilizer, which is a quick shot. Compost releases nutrients over time and will hopefully enhance my tree's growth.

In harvesting the worm castings, I chose the passive method: move the well-used bedding to one side of the composter, add in fresh bedding and only feed the worms where the fresh bedding is present. Three weeks later, I decided to remove the finished compost from the worm bed. Note that this was not a quick scoop up and use chore. No, despite moving the feed over to one side, many worms were still present in the compost I wanted to remove. In addition, I found many teeny, tiny worms in the compost. While this is a great thing as my worms are reproducing, the babies are much harder to see and thus, I took time to look at each handful of compost to remove the tiny worms. (I did decide to wear gloves when sorting through the compost and saved myself from the girly "Ew! I touched a slimy worm" reaction.) Since I wanted to preserve as many babies as possible, the careful scanning and moving to the good side of the worm bed took time. Regardless, I know I did not move them all, but if I moved at least 50% of the number present, I will call it good.

A few interesting things I noted as I meticulously looked through the compost:
Like humans, worms do not like to deal with cat hair balls. I found quite a few in the finished compost. Of course, these are not exactly like the ones I clean up on my carpet...
The crushed eggshells I added to the worm bed do not really seem to be necessary. I found many left in the finished side. No worries, the trees and plants like eggshells too.

So, what was my end product? Half of my worm bed yielded the compost in the picture below:

Beautiful, black, crumbly compost just begging to be used immediately. So, I spread it under my 28-inch tree and called it good!

To give you some idea of what I work with for my Pet Poo Converter, here is a shot of the closed lid, what rests on my basement floor:

And here is the bed now after removing the finished compost and replacing it with freshly shredded and wetted newspaper. I use only black and white newsprint for the worms. Much of the black crumbly stuff on the right side is due to me moving worms, tiny or otherwise, from the finished compost side.

So there you have it: my productive worm bed and their black gold. I am really excited this project is working out and the worms are happy to consume and reproduce. There is still the compost tea in the bottom of the worm bed I have not yet used, but since my rain gauge says we had 2.5 inches of rain in the last two days, I will wait before diluting the compost tea and watering my plants.

Edit: I checked the bottom of the worm bed four days later and was surprised to find many of my worms had escaped from the top section of the unit. I ended up having to move them back by hand onto the bed and cursing their rebellious existence. Why could they not stay where they belong? So much for only compost tea collecting in the bottom.


  1. Have to say, I'm a bit jealous! We got one of these same units, and for whatever reason the worms will not touch our cat's waste! They like the litter just fine though?! We have a separate unit for kitchen scraps that is doing fantastic, but our pet poo converter has been pretty much abandoned.

  2. Hi unsheeply,

    The compost may look good, but it was a struggle. I dropped cat poo on the bed and I swear it was not touched the first month. I thought it would rot before the worms would eat it. Hence, it is July before I harvested and my worm farm was started in March. I read that the worms need some grit so I crushed eggshells and added those. While I am not certain they really needed the eggshells since I found many in the finished compost, things started happening shortly after I did so.