May 27


How Should We Harvest Worm Castings?

Worm castings, harvestThis may not be the post you were expecting to see if you’re looking for step by step directions. I’ve been asking the question myself lately. How to harvest worm castings? Why have I been asking this? I have some friends working in soil food web testing labs. They are finding that many worm castings they’ve tested are surprisingly lacking life. We’re all told how worm castings are the best thing for plants and soil. How can it be if they’re so lacking in life? I began investigating and found a quote from Elaine Ingham:[spacer height=”10px”]

Feb 15 2016

Worm castings do not, willy-nilly, have more beneficial life than compost. I’ve been unfortunate enough to have looked at “worm castings” that are just as bad as the worst manure you have ever seen. So you can’t trust people to manage worms right either. However, if they do manage the worms aerobically, with good fungal foods, then worm castings and thermal compost and static compost can be every bit as good as the others.

How do you tell? MICROSCOPE

Elaine R. Ingham
President, Soil Foodweb Inc.

Ok, so I know some of the worm farmers whose tests were lacking life. These folks are doing a pretty good job of keeping beds aerobic. They’re adding what are considered fungal foods. What’s happening?

I continued to investigate, something was missing.

I was asking a lot of questions of worm farmers about methods: How do you harvest? How wet are your bins? what do you feed? what’s your bedding? The answers varied greatly but their tests were coming back similar.

Next I turned to the laboratory owners/workers. How are the samples arriving? What life is lacking most frequently? Consistently fungi and nematodes were the most often lacking organisms.

Finally I had something consistent, a trail to follow.

Eventually I had a conversation with Vivian Kaloxilos a student of Dr. Ingham who does soil food web testing in Quebec, Canada.

She made me feel like those cartoons where the lightbulb pops on above your head when she said:

“I asked a client to send me her sifted and non sifted vermicompost. I found twice the amount of fungi in the non sifted, plus tons of nematodes. In the sifted, the fungi was much lower and nematodes were barely present. This brings us to the issue where vermicompost producers need to harvest their worms and eggs from their product before giving it away. Its a catch 22”- Vivian Kaloxilos

This was what I’d been searching for! It would seem drying vermicompost to screen it or perhaps the agitation of screening was damaging the organisms in the castings!!

Now this begs the questions: How do we harvest castings without doing harm? Does the aesthetic appeal of finely sifted castings matter? How do we not give away cocoons or baby worms and still sell the best quality castings?

I’d love to see the readers comments and suggestions on this!!


how to harvest worm castings

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  • I appreciate you saying that worm castings, thermal compost, and static compost may all be just as beneficial as the others if the worms are managed aerobically and fed healthy fungal diets. My mother began working in agriculture. I'll mention worm castings as compost.

  • i will be very interested to see what people come up with by way of solving this problum.
    and all so the people that already sell worm casting how they will react to this new info. or would they care . my opinion is now. knowing this would you sell the worm casting knowing they are not as we thought. personally i would not. but i am relatively new to this and as such i want to do it the right way.
    Thank you LJ for bringing this to our attention.

  • Well this is what I am struggling with. I would like to see what I’ve produced (a subset that is) under a microscope.

  • It would seem that in the absence of drying/sifting, we have to resort to the old dump and sort. I’ve always kind of enjoyed it as you start to get into a rhythm and can turn off your brain. Whilst worms will migrate to the bottom of the pile and can be easily sorted, I do not relish the idea of having to sort out all the cocoons! Maybe you just have to admit that some will slip through the process and say that the castings are “extra organic” because they’ve also got worms built into them!

    • I don’t necessarily think we gotta stop sifting- just be aware that possibly making an extract from coarser casting may have a more positive effect.

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