Just had an interesting convo where someone was suggesting (or rather insisting) that worm castings (aka worm poop) is ‘toxic’ to worms.

A good topic for discussion I guess, as it’s not raised all that often.

The following was my reply…

‘You’re kind of on the right track.

Unfortunately there’s no such thing as 100% worm castings, hence the more apt terminology being… ‘vermicompost’.

Even after a screening process, the food source in the substrate is often plentiful, which the microbes and any wisps that have recently hatched can continue feeding on.

As a small commercial operator, we screen our vermicompost to produce a beautifully rich and friable high performing product that looks amazing. But with that said, we also have to take into consideration the presentation of the final product for sale. Therefore, we are a little more fastidious with that whole process.

This is also the primary reason for ‘curing’ finished vermicompost because it allows the microbes and any newly hatched wisps to continue feeding and further break down the leftover and unprocessed material in the vermicompost.

Many times in our final product storage systems I have discovered large healthy worms from either existing wisps or missed cocoons that have hatched, which have made it through the screening process.

This, in turn, has shown us they’re able to successfully survive and happily feed (microscopic protozoa is their preference) even when you think there’s nothing left in there to entice their appetite.
In a home system, it’s not necessary to screen your castings, unless you really want to. Simply removing your vermicompost from your farm and placing it into a separate tray with a bait system (butter / margarine tub with a few holes in each side filled with some bedding and food) will suffice and may take approx. 3-4 weeks.

This will also give the majority of new wisps the opportunity to hatch out of their cocoons and make their way to the bait tub, eventually leaving you with a beneficial living product which can be used as a valuable soil amendment or the ability to create a quality extract or activated aerated worm castings tea.

So, yes… consistently eating their own ‘poop’ may not be totally ideal. However, the likely hood of their castings actually being ‘toxic’ is not really much of an issue in the grand scheme of things.’

Hope that helps.

Chris 😊👍