Vermicastings and compost teas

Good morning. I learned from Dwayne Bowman with SoilCraft about how they are using vermicast tea to increase biology in commercial regenerative fruit farms in Washington. They buy their vermicastings, but I learned that what you feed the worms makes a difference on the quality of vermicastings.

After watching some youtube videos, I am trying to create high quality vermicastings here for my garden. I am feeding cow manure (grassfed and dairy mix), oak leaves, coffee grounds, kelp, azomite, and I am looking for a source of chitin.

On Saturday, I was talking to a guy that has a business of making compost tea and applying it to large fields. He commented that you need the soil biology to create organic matter.

Here are some questions that I would love to hear your feedback:

  1. Does it seem like a good idea to research and try “Appropriate Technology” ways to have small-holder farmers use compost/compost teas/vermicastings/vermicasting tea?

  2. Is it achievable to make quality composts and teas without microscopes and electric?

  3. Which is more important for a small-holder farmer a) use green manure/cover crops to increase organic matter and thus soil microbiology b) use biological tools to increase soil organic matter and soil biology, or 3) use both?

  4. What is your experience both good and bad in using compost/ compost teas/ vermicastings/ vermicasting tea?

In her book “For the Love of the Soil” Nicole Masters talks a lot about using vermicasting tea to convert from conventional farming to regenerative farming. It is a way to stop using commercial fertilizers.


I’m not a big expert (yet :wink: ), but I can give you an answer on question nr 2: yes, it is absolutely possible to create high quality compost without electricity and stuff. Compost tea might be more difficult, I’m in contact with the soil food web for more information on that one (whether stirring regularly instead of aerating would suffice).

Question three boils down to what a small scale farmer can afford. Plants do stuff for free if we let them. Biological tools (I assume you talk about stuff like vermicompost and compost tea and stuff) speed things up a bit, but cost a little more effort and/or money. We work in Central Tanzania, where people are very poor, so any financial investment is out of the question here…

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Hi Mike!

In response to question #2, here is a post from a few years back on our solar powered compost tea brewer prototype. It won’t be appropriate for every small-holder farmer, but I think its worth considering in areas where solar power is accessible. Take a look: Solar Compost Tea Maker - #6 by Elliott_Toevs


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I love the questions and I am definitely on the road mentally to learn about and try out different tea techniques. My answer to the first question, therefore, Mike, is YES! I listened to the Love of Soil as an audiobook and have focused on feeding our worms more carbon, including a lot of cardboard. I would love to hear other experiences. It will take money, but we have access to a good lab that tests compost (Universidad de Costa Rica en Montes de Oca, Centro de Investigaciones Agronomicas), so maybe we could try to semi-standardize three or four “diets” that would be comparable to what smallholder farmers would use, then test the results? To get a baseline of what the differences would be based on diet… Thinking out loud here. I think those thoughts are in response to question #2. Question #3 reminds me of our problems with soil pests (nematodes and root aphids!) plus our above ground diseases, like mildew and bacterial rots (anthracnose?). I believe the answer is both. We are covering six of our garden beds with Velvet Bean for two or three months, to keep the biology of the soil alive and well, but hopefully break the chain of infections and population with a resistant crop. Then we’ll continue to use the biological tools of vermicastings and mulching with compost (small, highly productive spaces, not for field crops) to maximize the biological diversity. I have been listening a lot to podcasts from No-till Market Growers ( ) and I am trying to apply the principles in our community gardens…

Also, in that forum, someone linked me to a resource that looks kind of awesome, . They have resources for all kinds of inputs, generally following Korean Natural Farming.

In terms of using teas, I have used a very cumbersome process of getting the exudate from vermicastings and using that to water recently planted lettuce, peppers and celery. It worked well with the lettuce and celery, not so well with the peppers. In terms of vermicastings and compost, we have used a mix of 3 buckets of carbon material (dried, semi-crushed leaves, for example), 1 or 2 buckets of compost, and half a bucket, or less of vermicompost, and a good amount of water, applied as a mulch. Sometimes this has had a hugely positive effect, as in I can see the lettuce beans and tomatoes perk up in less than 3 days, but I also suspect that it has resulted in our problems with the bacterial diseases. I switched out the leafy, barky material for somewhat expensive ground coconut fiber (that is readily available here) and voila, no apparent problem with the bacterial spots. So, still in the process of figuring all of that out. I also know that we need to compost our compost more thoroughly, We always need more, so I tend to use it in whatever stage it is in, regardless. Sorry Mike! Too much thinking out loud!

Anyone can do vermicomposting, especially if you have access to animal manures. We raise our worms in inverted tires, for example. That part of our system is pretty close to free. Getting the worms initially may be an issue. Also, getting the right worms for the environmental conditions. Asian redworms (“California worms”) are good for cooler areas, African worms ( Eudrilus eugeniae) do well in hotter, drier conditions. There is no way to overstate how useful these guys can be in agricultural systems.

The people where we live are in the category of “I don’t know whether I will have enough money to buy food tomorrow”, so any investment that will let them go hungry is out of the question. So, even vermicompost is a challenge (but doable). Compost tea probably impossible, as it needs electricity (not available, too expensive).

We could do it on our farm, but we are a model farm for small scale farmers, so we avoid using techniques that the poor people wouldn’t be able to afford.