Walnut Shell Vermicomposting?

Another “zipper bag worm bin” experiment I’ve decided to try is a system using walnut shells as a primary bedding (and maybe even food eventually) material.

I’ve been eating more nuts as part of an overall “improve my health” (which is just fine – thanks for asking – but there is always room for improvement) plan, and walnuts have become a favorite. The ones with shells on them are naturally the cheapest at the store – and in my humble opinion, the quality of the nuts inside is better – so those are the ones I tend to gravitate towards.

Being the worm-head that I am, seeing all the walnut shells piling up in my kitchen scrap bags got me wondering how they would break down (how fast etc etc) in a vermicomposting system…and that got me thinking it might be fun to test them out as a primary system material.

Obviously, like many nut shells, these things are pretty tough and resistant – almost certainly on the high end of the C:N scale. So, I’m not expecting them to get converted into beautiful worm castings in no time flat – that’s for sure.

Still, my hunch is that they will likely break down a lot more quickly than something like wood chips. And I suspect they will have some other components (eg nut fragments) that will add additional nutrition.

Whatever the case may be, it should be interesting!

All I did to get things started was put some shredded corrugated cardboard down in the bottom of a plastic zipper bag (figure having a more absorbent false bottom is not a bad idea), added a small handful of dried beans, rice a barley along with a small amount of living material, before filling the bag almost to the top with walnut shells (+ fragments etc) that I’ve been collecting.

Lastly, I just sprayed everything down well (since the shells won’t really release moisture), closed the zipper about half way and then put on my seedling heating mat.

At this point I am just going to leave the system to brew for a while. I am interesting to see what sort of decomposition processes will get going (with the help of the extra warmth). Similar to my 4 Worm Zipper Bag project, I’ll likely wait (at least) 2 weeks before actually adding any worms.

Stay tuned! Lots more to come.

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    • Rafael
    • May 14, 2017

    Hi Bentley

    Interesting experiment. Any updates?

    I’d guess the shells would take a long time to break down…

    • Bentley
    • May 18, 2017

    I have just been slammed this Spring, Rafael – so unfortunately no updates. I do need to check up on the bag at some point! lol
    Thanks for the nudge

    • Drew
    • September 14, 2017

    Any update in this Bentley?

    • Bentley
    • January 12, 2018

    Rafael and Drew – I just posted an update relating to this topic:

    • Brenda
    • March 30, 2018

    I’ve added pistachio shells to my worm piles. I soak them in a few water changes to get rid of the salt and mix them in with the food. They do eventually rot and disappear.

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