Pre-Composting Then Vermicomposting

John Augenstein
#1. August 14th, 2008, at 4:48 AM.

To set the stage, I’m raising eisenia fetida in my garage in three 30 gallon plastic tubs. I harvest the compost at a rate of one tub each month.
I’ve been experimenting with pre-composting worm food for several months now. I started by using material directly out of my compost tumbler which consisted of about 50% completed compost plus material in all stages of breakdown since I add garden trimmings, grass clippings and overripe vegetables on an ongoing basis. The worms do just fine with it and I don’t have an excess water problem in the worm tubs but it’s a much denser food and I had to cut my quantities at feeding time about in half. Overfeeding this stuff doesn’t bother the worms but it does reduce the quality of the vermicompost somewhat.
About a month ago I was given a half watermelon that was past it’s prime. It was’t a good time to feed, so I chunked it up and layered it into a 24 qt plastic pail with a pile of 1″ squares of cardboard from a cardboard box. The mix was about 25% cardbord and the balance watermelon. I laid a piece of plexiglass over the top of the pail to keep the flies out and promptly forgot about it. About a week later I remembered it and found the bucket was only about half full. The watermellon was reducing and giving up water. I poured of the water, which was cloudy and smelled like vinegar, then dumped the contents back and forth between two pails to areate it and put the plexiglass back over it for another week. It further reduced to a little less than a third of the pail. I poured off the water again and fed the remains to my three tubs by laying it on the top of the bed. When I pulled the covers off the next day to check the worms, I almost couldn’t see the food for the mass of worms all over the top of it. This was true of all three tubs.
I have just set up four more pails as follows:
1. Watermellon and cardboard (to duplicate the test)
2. Watermellon and chopped wheat hay
3. Squash/cucumber and cardbord
4. Squash/cucumber and grass clippings
I’ll get back to you when I have more results.
I hope there’s something helpful here.
John

Sherry
#3. August 16th, 2008, at 12:52 PM.

A few weeks ago I had a lot of watermelon rinds. I kept them in a container in frig and fed them as needed to the worms. They couldn’t keep up, so the watermelon was in the frig for quite a while. Just last week I checked the bowl and there was a lot of cloudy liquid in the bowl, and a lot of white slime on the melons. I poured it down the drain, and put one piece of melon in each bin. I was concerned that it might be starting to ferment, so didn’t want to overfeed.

The next morning I checked and that was the busiest spot in the bin. Hordes of worms under the melon loving it. They promptly got the rest of the melons. I think they were liking the fermentation, alochol!

Shawn
#5. August 21st, 2008, at 3:39 PM.

With respect to large-scale vermicomposting - we also pre-compost to limit the further composting potential of the feedstock material once fed to the worms. The last thing we want is for our worm beds to start heating up due to a composting action. Weed seed destruction and pathogen destruction are also big factors for us (from a product liability standpoint). Many of our large greenhouse clients would not be happy if weed seeds were passed along to them (neither would I). All in all - I think it really helps in providing a very stable material for the worms.