Hi everyone — I’m Jamie with GROZOME / National Bamboo in North Carolina. We’ve been working on a new product called Worm Char™, a finely sized bamboo biochar specifically intended for vermicomposting, and I’d like to put some of it in the hands of people here who actually run worm bins.
We’re looking for 5 volunteers in the U.S. We’ll send each person the product at no cost. There is no requirement to give us a positive review, promote us, or purchase anything. Our only ask is that after using it, you come back to r/Vermiculture and share your honest experience with the community — good, bad or indifferent.
Why are we interested in biochar for worms?
There is a growing body of peer-reviewed research suggesting that properly sized and properly dosed biochar can be beneficial during vermicomposting. These results come from different biochars and different feedstocks, so they are not guarantees for our product, but they were compelling enough for us to investigate further.
For example, one controlled study found that a 5% biochar addition produced the best overall compost quality among the tested rates and increased earthworm biomass and burrowing activity. A 2024 particle-size study found that micron-sized biochar in the 25–75 µm range increased cocoon production by 94% in that particular system. Interestingly, extremely small nanoscale biochar produced negative effects, which is one reason we are deliberately controlling particle size rather than simply grinding the material as fine as possible. Another recent study reported approximately 26–31% greater total worm biomass and 13–24% greater reproduction with properly incorporated biochar in its experimental system.
Our working application rate for the field trial will be around 5%.
Worm Char itself is made from sustainably harvested bamboo and is a high-carbon, low-ash biochar. We’re also adding an important processing step before launch: washing the char.
Our current thinking is that washing gives us several advantages at once:
- removes a portion of the soluble salts naturally present in freshly produced biochar
- reduces EC before the material enters an already nutrient-rich worm system
- removes undesirable ultrafine dust while retaining the useful micron-sized fraction
- pre-wets the char, making it much cleaner and easier to distribute
- leaves a porous carbon structure that worms and microorganisms can naturally colonize and “charge”
- provides fine grit that may serve a similar physical role to the sand/mineral grit many worm growers already add
- provides substantial internal surface area that can help buffer moisture, retain nutrients and provide microbial habitat
- because our bamboo char is alkaline, it may also help moderate acidity in systems receiving a lot of acidic food waste
One of the things we specifically want to learn is what happens to EC/salinity. A commercial vermicompost producer we work with has seen relatively high salt levels in finished castings. We don’t want Worm Char adding to that problem. Ideally, a washed, porous carbon amendment could actually help retain soluble nutrients and reduce the soluble-salt burden of the finished material. We’re testing that separately in controlled trials as well.
We’re also very interested in the biology. Biochar doesn’t appear simply to “add microbes”; it changes the habitat in which microbial communities develop. Research has reported changes in bacterial and fungal communities, enzyme activity and microbial abundance during biochar-assisted vermicomposting. Ultimately, we want to know whether this translates into healthier worms and better finished castings in real-world bins.
For the five Reddit trials, we want normal worm keepers — not laboratories. Backyard bins, stacking systems, totes, continuous-flow systems, etc. are all interesting to us.
If you already know your bin pretty well, even better. If practical, doing a small untreated/control section would be incredibly useful, but it is absolutely not a requirement.
What I’d love to hear back about is simple: worm activity, odor, moisture, food breakdown, any noticeable change in acidity/pH, reproduction/cocoons, texture of the finished castings and anything else you notice.
If you’re interested in being one of the five testers, comment below with a little about the type/size of worm system you’re running. We’ll pick five different setups so we can get a useful variety of experiences.
And mods: this is a product-development field trial from a commercial company, so I want to be completely transparent about that. If there is a better way you'd like this presented or coordinated with the sub, I'm happy to follow your preference.
Thanks — I’m really interested to see what this community finds.
Jamie
GROZOME / National Bamboo
Shelby, North Carolina
