Urban Worm Bag – 01-14-19

Back near the beginning of December I wrote about my plans to (finally) get my Urban Worm Bag 2.0 up and running – and to do so with a bit of (controversial?) flair!

Rather than simply starting yet another kitchen-scrap-processing system, I thought it would be fun to test out cat litter wastes (from a box that uses compostable, clumping litter) as a worm food.

I had originally planned to try processing everything, but another experience vermicomposter – who has been processing cat wastes for quite some time – talked me down from the ledge (haha), suggesting it might make more sense to avoid the urine-soaked clumps (especially since I am using chick starter feed as the litter – a very high-N material already).

So processing ‘kitty poopies’ (mostly) it is!

Disclaimer – Figure I had better get this out of the way (lol). Please keep in mind that I have been vermicomposting for nearly 20 years, and this is simply intended as a fun experiment “for entertainment purposes” only. Please do not attempt this at home (especially if you are new to vermicomposting)! I cannot be held responsible for any ‘poop’ hitting the fan, should you decide to do so!


Things were of course busy over the holiday season, so I didn’t end up having time to get my Vermi-Bag system harvested and moved out of the basement bathroom to free up space for the UWB (until recently). But as subscribers of the RWC e-mail list will know, I DID end up setting up a sort of “pre-vermicomposting” bin. It was actually the old “bananas and walnuts system” (unfortunately a project that kinda fell by the wayside last year), with some wood chips, aged horse manure – and of course cat wastes – mixed in.

Rather than stocking with worms – my first plan was to simply use Red Worm cocoons, easily/quickly harvested from the “rescue bin” I mentioned in my recent Euro post. All told, I ended up adding at least 350 cocoons – in other words, potentially 1000+ “future worms” (since the average number of hatchlings per cocoon is usually around 3).

I liked the idea of cocoons since there is some research to indicate that worms hatching into a particular environment tend to be better adapted for that environment than any worms that are introduced. I’ll talk more about why I ended up changing my feeling about this (and what steps I took as a result), a bit later on.

Well, obviously I did finally have time to harvest and move the Vermi-Bag system and stand (last week), so I got busy with setting up the new UWB system not long after. Right off the bat I was impressed with the improvements in the 2.0 model (I wrote about here: The Urban Worm Bag 2.0)!

I’m loving the new double zipper lid and drawstring opening down in the bottom – and the corner pieces definitely do look more sturdy!

The set-up process was quite similar to pretty well every flow-through-bag system I’ve set up before. I started with the “false bottom” zone – although in this case, I’ve decided to just use the drawstring zone as my “bottom”, with the zipper flap just staying wide open.

This should help to keep things even more “breathable” down in the bottom.

I was amazed by the amount of shredded (brown) paper I was able to deposit down in this pocket – pretty much an entire 3 gal pail full (although it definitely doesn’t look like it in the next image)!

Then, it was time to add lots of newsprint layers. I normally prefer actual newspapers for this, but at this point I really don’t think there is much of a difference between them and the color flyers (non-glossy) I ended up using – so much colored ink in newspapers these days anyway.

I sprayed down these layers fairly well with water to help get them stick to the side walls.

Next, I added a mix of different materials – shredded cardboard, stove pellets, along with some fairly dry, aged horse manure. This might be considerd to be a hybrid zone – absorbent benefits of a false bottom, with some nice habitat/food material in there as well. I sprayed this mix lightly – so as to make it a bit more worm-friendly – but wanted to leave it fairly dry so it would be able to soak up lots of moisture over time.

It was then time to dump in my “pre-vermicomposting” bin. Digging around a bit, it looked as though at least a few worms had hatched out already – but I didn’t do any sort of serious assessment. All this material brought the level up very close to the top of the newsprint – which I think is just about “perfect” for now (since it reduces the chance of worms crawling in behind and down).

Normally, I would next add a really thick layer of cover bedding (and I highly recommend this if you are working with kitchen scraps), but I already feel like this habitat is a little on the dry side, so I decided to hold off for now – simply opting to lay a loose garbage bag over top instead (my new favorite type of cover/lid for most of my systems).

The zippered lid was then partially closed (I still want to ensure as much air flow as possible).

OK – getting back to my change of heart about the worms…

I noticed a few gnats here and there once I added the material from the bin. I feel pretty good about the predatory ecosystem (predatory mites etc), largely thanks to the aged manure – but I don’t really want to take a chance on it. Plus, I just want to see this system hit the ground running, since it has already been more than a month since I first planned to get it set up!

So, I ended up transferring over a small bucket of worm-rich material from my Vermi-Bag system as well (a bit later on). I’ve also decided to supplement the system with a bit of water-rich kitchen waste – so far just a single, soft eggplant I found in the fridge (yeah, it was on the way to being rotten…honest!! lol).

I have little doubt the worms will love the cat wastes – but I think a little bit of supplementation with more typical materials can only help them thrive in the long-run!

I am definitely excited to see where things head from here.
Do stay tuned!

And once again…

Disclaimer – Please keep in mind that I have been vermicomposting for nearly 20 years, and this is simply intended as a fun experiment “for entertainment purposes” only. Please do not attempt this at home (especially if you are new to vermicomposting)! I cannot be held responsible for any ‘poop’ hitting the fan, should you decide to do so!

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    • RJ
    • January 19, 2019

    Hey Bentley – just curious about the garbage bag on top. I have two regular worm inn systems and wondered if the garbage bag would help retain a bit more moisture.

    • Bentley
    • January 23, 2019

    Hey RJ!
    I love using them for extra moisture retention. With plastic tub bins I almost never even use lids anymore – just lay loose garbage bags over the surface. Definitely recommended for a Worm Inn since even more air flow (I have one in my Vermi-Bag as well)

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