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A spot of tea…

Compost tea in a barrel

Steeping compost in water is all it takes to come up with a healthy batch of…compost tea. Here we’ve taken some composted cow manure and let it sit in a 55-gallon barrel of water for a few days. There are different methods, ingredients, and all kinds of other details about preparing this stuff, but I’m still in the broad strokes experimental stage: I make it up somewhat differently every time. This time, three barrels are going around the field, strategically placed next to mesclun beds and spinach. Hopefully the small amount of nitrogen, assorted micronutrients, and other possibly unidentified good things will give these late season plantings an extra growing boost! They’re used diluted maybe by half, applied with good ol’ watering cans, then soaked in hours later with a solid hose watering. Veggies don’t get more hand-tended than that! :)

(NOTE: There are different types of “compost teas,” different ways of making and using them, and lots of different opinions about all of this. If you’re thinking about making your own compost tea, a couple of good places to get some quick, general info are Wikipedia’s Compost tea article, and ATTRA’s Notes on Compost Teas.)



  1. Steve Mudge

    That looks a lot easier than the method I was reading about which, as you say, can be a lot more technical. Is “partially composted” cow manure the same stuff you’d buy at the nursery for planting with or do you have to find something fresher?

  2. I remember a few mornings of hand tending vegetable plants — it is daunting to look down the row and see another 1000 plants you still have to deal with. That is one of joys, though. You just have to pull that head down and concentrate on each plant until you are done.


  3. Steve: The by-the-book thing to do is use fully composted manure, stuff that’s been continuously heated for a while so evil PATHOGENS get killed, if they’re there at all. My “partially composted” I could call just “compost”, it’s pretty much what you’d buy at the garden center. It’s just not off my usual compost pile… From what I’ve read, most of the time “manure tea” actually refers to compost tea, but then there are those who recommend dumping a few shovelfuls of raw manure into a bucket (pathogens and all?!). I’m…experimenting. I don’t have my own tried and true methods just yet (and I haven’t tried raw manure, so far, just to be safe)!

    Simon: Yeah, if I had to pick one aspect of small farming that’s absolutely different from…city life, it’d be facing a field full of hand work. There’s the incredible satisfaction of gambling with nature and watching things grow, and seeing what an effect your own timely or untimely intervention can have. And then there’s a lot of routine work that could seem incredibly tedious. After the initial year or two of microfarming novelty and “will this work” adrenaline wears off, it’s a steady process of letting the routine settle in along with all of the other new awarenesses. There are definitely tough, daunting days, but you can feel a new, uh, consciousness coming through. When I do stuff with Bob, who’s farmed for decades, the feeling is clear. I’d say it’s maybe what most defines farmers trained from childhood, the kind of attitude toward getting jobs done. It’s not “factory work”, you feel your little efforts are directly part of a Big Picture, like, the whole planet!! There’s deep, quiet, ongoing satisfaction to be had from really “boring” looking repetitive tasks in and round the field…has to be tried, harder to learn late—a cool state of mind! Hope I get all the way there! :)

  4. Green Tea

    Its a great posting..keep it up..all the best..That looks a lot easier than the method I was reading about which,steeping compost or manure in water is all it takes to come up with a healthy batch of…compost or manure tea.

  5. Iyad


    what’s the time required for compst tea to show results on the plant

  6. lyad: It would depend on the type of compost or manure tea, what went into it, how it was made. A tea made from manure will probably have more nitrogen and other plant nutrients, and that effect should show up quite quickly, in a few days, maybe quicker. You can apply the tea to the leaves (foliar feeding), and that would likely speed things up as well. On the other hand, if you have a compost tea that is mainly beneficial organisms and food for them, and the intention is to have them multiply in the soil, that result may be more subtle and over a longer period.

    I’m just getting started with serious composting and compost teas. This year, at the new farm, where there is no handy supply of cow manure, I’m going to be relying on it a lot more. It should be interesting. I’ll report!

  7. Malcolm Morrison

    When making a compost tea it is important to keep in mind what your final goal is. Are you wanting to make an organic nutrient that has N-P-K’s (nutrients) or are you wanting to inject to your existing soil food web beneficial microbes (bacteria, fungus, protozoa and nemetodes) to aid in digestion and chelation of existing organic N-P-K’s.  Because of the mechanics of soil and its intense buffering capacity organic nutrients take a long time to break down and become available for plants. In this time it is easy to get “out of balance” chemistry happening in your soil which results in lock outs. For the sake of this post lets assume you are wanting to create beneficial microbes to help break down nutrients and not use for nutrients.
    Healthy compost tea that is rich in beneficial bacteria, fungal content, protozoa and nemetodes will help keep your soil eqaution in balance. In my experience a bucket or conatiner with manure in it with water simply set out for a couple of days to weeks can encourage “anaerobic” decomposition. This simply means that there in no oxygen available and can actually encourage bacteria and protozoa that you would typically not want to introduce to your growing environment, escpecially in a greenhouse or closed environment. The healthiest teas you can make are always aerated with some type of air pump and do not contain any manure. Compost made from greenwaste or digested greenwaste from earthworms is typically the best route. Worms do not contain a lot of the pathogens that animals like cows and horses due in their digestive track. They actually contain a lot of the bacteria that you are trying to capture in your tea. You then need a food source to encourage those bacteria to grow in your tea and give you an end result of a liquid rich in the bacteria and fungus from your compost. In essence think of the compost as a growing media for existing beneficial organisms and you are  moving them from a one bedroom studio to a 5000sq ft house and the food source is the catayst.
    The food source is another intersting topic, for ease and sake of complexity pure molassas is the most commonly used, however there is discussion on this but to get started this is the easiet.

  8. Malcolm: Thanks for the detailed info! I see from your link that you’re in the compost tea/beneficial bacteria business. Cool! I understand what you’re getting at, and I appreciate the compost extract vs aerated, food-added brewing methods and products. I updated the post, adding a note at the end to a couple of places to read more about different types of compost tea and extracts.

  9. Malcom Morrison

    Mike, no prob, I love spreading the word of healthy biology. 

  10. bruce y. garcia

    Hello i have wondered how much you would charge to set your theme up on my blog for me, because i really like the look of your internet site but i don’t know how to set such a good graphic.

  11. Kevin Nistler

    I have compost worms that I collect the tea from all winter and store in milk jugs in a heated garage.  Is it still good, and can I use it this Summer.  We live in Alaska.

  12. Rose Bush Care Tips

    What about the possibility of E.Coli from the making of Compost Tea. In the beginning I have heard if you use a manure based compost it can result in high levels of E.Coli in production, but it should go away after a while. But if there is a regrowth and then used on edibles it could cause E.Coli poisoning.
    How do you deal with this?

  13. Kevin Kirschner

    Hey Kevin, I think you should place your compost worms in your compost tequila.  They will be well-preserved that way.

  14. Kevin Nistler

    I have a 7 tiered worm compost bin (can o worm)that I feed my worms produce in.  I have been doing this for a few years however I have just gotten spideres in the bins.  Very small microscopic, red and tens of thousands of them.  Has anybody seen theses?  Is there any way to lill them and not my worms?  Will they devestate my worm population?  I store these in my heated garage that is attached to the house.  Any chance they will get into the house?  Thanks Kevin

  15. my God, i thought you were going to chip in with some decisive insght at special end there, not leave it with ‘we leave it to you to decide’.

  16. Hello Compost tea brewers.
    I just spent a year writing a new book on this subject titled Compost Tea Making.
    The intention was to use modern data and experiance to endeavor to clarify some conflicting ideas and techniques used to make compost tea and EM products. I interviewed a microsposist who’s whole gig is to use the microscope to really see whats going on before, during, and after brewing compost tea. That is the bottom line.
    Many gardeners I have spoken with that make “compost teas” have very vague ideas about what they are actually doing, and use techniques that I now, with the knowledge that I have gained, consider inadequate and unsafe.
    The most reliable, safe style capable of producing the highest microbial content is the aerobic style. It is really easy to set up an air pump in your barrel or bucket. if you do not, like this method as described in this blog from 2007, your brew may be culturing stinky anaerobic little nasties. With all due respect to the author there are better ways to do this– and not really difficult. With an air pump and a little molasses you can produce billions more bacteria. With the addition of kelp and other additives the fungi population will also be much greater. Check out my blog site

  17. Raon

    Read a lot about compost tea and all and I tried to make one for my bonsai trees. I brewed cow manure for a day with an air pump. The next day I poured a bit on my favourate bonsa tree and instantly all the earthworms wriggled out of the soil and died. I just hope my tree survives.

    To salvage this i had to leach the soil. there was a lot of soil erosion. ifeel bad for my little friends.

    I would aidvse If your plant is growng right then pls dont do any thing silly.

    And yes… earthworms is the farmers best fr

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