Tuesday, July 15, 2008

Harvesting the Vermicomposting Bin

Yesterday we harvested our vermicomposting bin in order to obtain the useful worm castings they have been producing. As you can see (below) the level of material in the bin decreased dramatically over the 3 months as the worms broke down their bedding and the food scraps I gave them. The original level was near the top piece of duct tape.

There were several steps involved in the harvesting:

1) Preparing new bedding for the worms. - We did this in a large recyclables bag, in which we shredded newspaper just like the first time we made bedding for our worms. It was easy to moisten the newspaper with water and estimate the amount of bedding we needed in the bag.

2) Piling and Sorting the bin's material into 3 basic containers: worms & reusable bedding material, worm eggs (to avoid overpopulation and eggs hatching in plant pots), and the worm castings (what we're doing all of this work for!). We taped two cut open recycling bags together to create a large plastic sheet to line the balcony to do our sorting work on.

We used the pile & sort method where we emptied the bin's contents into several small cone shaped piles. The worms buried down to the bottom of the piles to avoid the light and we, pile by pile, scraped off the tops of the piles to get the vermicompost, working our way to the bottom. This was a very long and tedious process as we did a very thorough job. There were so many baby worms which were at times difficult to pick out and did not move down away from the light as well as the adult worms did.

This is what the bottom of the bin looked like after taking much of the vermicompost out. It's amazing to see what a job the worms did on that newspaper!

Piles for sorting

Pie plates helped with sorting
The Results

Two containers full of worms (below)

Collected worm eggs. Not sure what I'll do with these yet. I've read they can last many years. I am kind of playing god when it comes to the population of my worm bin (removed a little less than half of the population, and most of the eggs - they'll just produce more anyway), but I kind of have to because overpopulation would be a bad thing.
Total amount of Vermicompost collected! Several pounds (about 3/4 of that ikea garbage can is full)
Poo poo la poo poo la poo poo la pooGardener's Gold!! Harvesting all of this natural fertilizer I helped produce with my own food waste was really satisfying! Harvesting was hard work, and since the next harvest will be in late summer/early fall, I'm going to try a different method whereby I just push all of the bin's contents over to one side, fill the empty side with new bedding and food to draw the worms over, then harvest the empty side. The way we did it produces a much purer end product which I was only really concerned for when used on my indoor plants (i.e. I don't want any missed worms trying to live in my indoor plants). I have decided I will make some vermicompost tea for use on my indoor plants, thus alleviating any of these concerns.

3) Returning the worms to their new bed, while removing some of the worm population to avoid overpopulating the bin.

We added the larger container's worth of worms back into our worm bin, with freshly prepared bedding material (moistened shredded newspaper, hay, soil, some egg shells, undecomposed bedding from before). We contributed the remaining worms to the community composter in the park by our apartment building, which from what I have heard, has run out of red worms.

To come: Using the vermicompost in my balcony garden & making vermicompost tea!

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