Microbial Soup

I recently wrote about the little “Worm IV” rig I have hanging over my Worm Inn. What started as a nifty way to keep my Worm Inn hydrated, has turned into a fun little experiment to test out liquid feeding methods.

Let me point out right off the bat that this isn’t really particularly relevant for those of you who are using plastic enclosed worm bins, or even for the average hobbyist vermicomposter in general – this is just me having some hair-brained fun! I have a background in (and keen interest in) aquatic biology so I love finding ways to tie the two together (hence my fascination with topics like “vermiponics“).

I DO, however, think this (drip feeding stuff) might offer some potential for those who are interested in breeding lots of composting worms without the need for using food waste, manures or commercial feeds. The big question I have is whether or not paper-based bedding materials drenched in a nutrient-rich broth will support worm growth and reproduction to the same extent that some of the more typical “foods” do. Some of you may recall that this is something I’ve briefly explored before (see “Making Microbes” and “Making Microbes – Part II“) – but I don’t think I ever ended up really testing it out all that seriously.

As mentioned in the last Worm IV post, I decided to start using water from my daughter’s fish tank in my drip system. I figured there would be plenty of nitrogen (and likely lots of microbes as well) that could help the carbon-rich bedding materials to break down more quickly – thus offering the worms a more-readily-available food source.

Since then, I’ve taken things a step further and have actually started brewing up my own “microbial soup” in much the same manner as one would brew a compost tea. I put a small clump of dry alpaca manure in a mason jar filled with fish water, then added a small amount of molasses. I am oxygenating the mixture with a small aquarium air pump.

I started the brewing process yesterday morning and checked on the mixture throughout the day, but the only change I noticed was the slight “tea” tinge the water had taken on. The water was still very clear when I took a peek yesterday evening. By this morning, however, the water had become quite cloudy – so I’m confident that the microbial population has increased substantially. I took a whiff just to make sure it wasn’t going anaerobic and couldn’t detect any bad smells, so I think it should be completely safe to use (as I discovered the last time around, adding a stinky brew to a worm bed isn’t necessarily the best idea!).

Aside from continuing to drip down into the Worm Inn, I may also set up a small experimental bin or two. It would be interesting to see how cardboard soaked in this liquid compares (as a worm food) to cardboard soaked in aged tap water.

Anyway – I’ll keep everyone posted!

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    • Ted
    • November 15, 2010

    Dr. Wormenstein I presume.
    Not knowing this type of lab work, I find a couple questions that comes to mind.
    Will the surrounding temp of the mason jar speed up or slow down the microbs that are growing inside. Meaning, if it’s warm, the microbs will increase faster than if it was cool.
    And if a liquid rich broth did in fact break the carbon down and keep worms healthy without food scraps. Could it be used on outdoor bins in colder weather, when worms seem to shut down? I hope you know or anyone that’s reading this understands what I’m trying to say 🙂

    • Ted
    • November 15, 2010

    I have one other thing to add.
    If you were to have a worm broth ready to go, and placed it outside in the colder weather, would the microbs survive? or would the numbers of microbs decrease, like bacteria on food, 40 degrees or below?

    • Larry D.
    • November 16, 2010

    Call this one”Perry Mason jar!” Can he solve this case? No way,i would have thought of this one.But beings as i just so happened to buy the stuff for making a batch of V.compost tea.Looks like i will have to give a little to the wormies!
    My question is a more complicated one.I heard you can use honey instead of mollasses.But honey having a natural anti-biotic.What does this do to the microbes?

    • Bentley
    • November 16, 2010

    TED – Temperature definitely has a major impact on microbial growth/activity. Also affects oxygenation – warmer water can’t hold as much oxygen as colder water. So it’s probably a good thing that my basement is fairly cool.
    It’s not so much that the broth breaks down the carbon – its that the ample nitrogen it contains helps those microbes that break down resistant materials. If you mix cardboard with manure, for example, it will break down more quickly than if you simply soak it with water.

    A warm (indoor room temp) broth poured into a cold outdoor system could likely help to stimulate some heating action, but it would be important to have some good insulation.

    As for leaving the broth outside, this would definitely cause a slowing of activity, and would likely cause a lot of the microbes to go dormant.
    LARRY – Interesting question. I think it’s sort of like using a small amount of chlorinated water. Perhaps you will end up killing off some microbes, but I suspect it would be fairly minor.

    • Anna
    • November 16, 2010

    If you were to put this broth into an IV bottle, how would you keep it aerobic? (Or, is your drip method faster than I’m imagining?)

    • Zeb
    • November 17, 2010

    This is all very intriguing. I can see how this would work and would be a much cleaner process. If the worms eat exactly what they usually do, microbial organisms and carbon based material, the resulting castings would be exactly the same as if they are coming from food wastes or aged manure. The only thing I can think of for the health of the worms would be the presence of gritty material to clean their gizzards. A couple handfuls of sand would do it I suppose. I feel compelled to conduct a similar experiment, the control being the same bedding but with food scraps and the same amount of non-microbial, aerated water.
    Would this be a daily feeding schedule? How long would the microbes survive without a food source other than the sugar in the soup? Would the worms be getting all the right nutrients from a diet of microbes whose diet has been molasses and fish water?
    It would be interesting to trace the nutrients from the fish to microbes to the worms to the plants….to the worms….to the fish….to the microbes… Closed system? the only thing coming out would be tasty vegetables and pounds of worms.

    • Bentley
    • November 17, 2010

    ANNA – Great question! It has turned out that the drip speed is indeed faster than I reported in a previous post – but the key here is that I’m actually not all that concerned about the liquid going anaerobic while it sits in the drip bottle. Before getting anywhere near the worms, the liquid will soak into multiple layers of bedding where it will more than likely get re-oxygenated (lots of surface area exposed to air). As long as I can keep the main supply of “soup” from getting too stinky and foul we should be ok.
    ZEB – I will definitely be interested to see how this turns out in the long run. So far I’ve been impressed with how the system seems to have “come to life” a bit more now that it’s nicely hydrated etc.
    Do keep us posted if you decide to do something similar!

    As it stands, I’ve been doing two drip bottles per day. Seeing all the nice sludgy stuff accumulating in the main soup-production bottle has me thinking I might want to ramp things up a bit by manually squirting (with an old turkey baster) in some of the goop as well. I am not 100% sure about the nutrient profile but I suspect that the fish water would be pretty good on its own (since the fish food likely contains a reasonably amount of nutrition), and even better with the alpaca poop “floaters” (haha).

    • Kuan
    • November 19, 2010

    It doesn’t surprise me the fish tank water works well for worms. I have a fish pond and string algae seems to love the waterfall steps. Instead of feeding the string algae to the big compost piles, I fed them to the worms. They LOVE the string algae. Lots of them weaving in and out of the algae. I can grab a handful and dump them in the FT. Within days, worms are all over it.

    • Larry D.
    • November 21, 2010

    How do you think kelp extract would work? I tried some agricultural lime in my bin yesterday.But when doing my vermicompost tea research,i noticed it may be beneficial to try a drop of the kelp extract in the worm bedding.I will try it today.
    By the way.The used vermicompost for the tea,i put back in the bedding,the worms seem to love.Recycled vermicompost! 🙂

    • Bentley
    • November 23, 2010

    KUAN – That’s really cool. Thanks for sharing!
    LARRY – Not really sure about the kelp. As long as it doesn’t contain too much salt (definitely a concern if one were attempting to actual vermicompost a bunch of kelp) it should be fine. I know people swear by it for various “tea” mixes.

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