Found this. It's good to gather as much info as possible so we can make informed decisions. Good read!!
Here is info from MicrobemanMore on Compost Tea (2013) I've decided to add this additional information in response to many inquiries I've had. You will find much of it redundant but better too much than too little, at least in this case.
In my opinion compost tea is poorly named. It is not something one drinks and it is not created by steeping in boiled water as is tea. Aerated compost tea making is an active process which extracts microorganisms (breaks them loose from binding spots) into aerated water and provides them with a food source (foodstock) which causes them to multiply.
A more apt name would be a microbe multiplier and the process is almost identical to a laboratory device known as a bioreactor. Actually we have attempted a name shift by calling our new 12 gallon device an airlift [vortex] bioreactor. This, in my opinion, is a more descriptive term for what is going on but it looks like the term compost tea is going to stick.
If one is using quality compost or vermicompost (hereinafter referred to as [vermi]compost), an efficient ACT maker with sufficient aeration and the correct amount of foodstock, like black strap molasses, it is all about timing and to an extent temperature.
One must, of course use water which is free of chlorine/chloramines. This is easily done by putting a bit of molasses, ascorbic acid or a bit of [vermi]compost in ahead of time, which neutralizes these oxidizers.
The first microbes to begin dividing and growing in ACT are bacteria/archaea and fungi (if present in the [vermi]compost). The fungi grows out rapidly as fungal hyphae and is often attached to pieces of organic matter free floating.
The bacteria/archaea can divide every 20 minutes and appear as moving (motile) or stationary (non-motile) dots, rods and long strands. Usually these organisms are seen in large volume by the 18 hour to 24 hour period of the process, which for simplicity’s sake we’ll call a brew (since that is the term which has been colloquially applied).
In response to the population explosion of bacteria/archaea we have a congruent reactive increase in the protozoa population beginning around the 24 hour period. The usual type of protozoa which we see, given an efficient brewer is flagellates, however sometimes there will also be naked amoebae. The third type of protozoa, which we do not wish to see a ton of, are ciliates, as they can indicate the presence of anaerobic bacteria. The flagellate population can double every 2 hours so usually at the 36 hour period we have a sufficient diversity of microorganisms to call the brew finished and apply it to the soil and plants.
A good temperature range is usually 65 to 75 F but unless really cold the timing estimate is quite reliable.
Why use compost tea?
The main reasons for using compost tea are;
1/ to provide a quick nutrient kick to the rhizosphere. This works mainly because as the flagellates (protozoa) consume the *bacteria/archaea they utilize only 10 to 40% of the energy intake for their sustenance and the remaining 60 to 90% is expelled as ionic form nutrient which is directly bio-available to the roots of the plants. This is known as ‘the microbial nutrient loop (cycle)’.
2/ to begin or continue an inoculation of the soil with a microbial population. Many of these microorganisms will go dormant until called upon later to fulfill their purpose but many of them will grow and flourish, finding their station in the hierarchical positioning of microbes in a living soil. Some, like the fungi will grow out through the soil binding aggregates together, assisting with air and moisture retention, providing pathways for bacteria/archaea, providing a food source for various microorganisms and degrading organic matter to a point where it is available for other organisms.
Within a very diverse ACT there will be free living nitrogen fixers, anti-pathogens and yes a few of the anaerobic and facultative anaerobes which serve their positive role in a living soil.
3/ to potentially provide the microorganisms which may assist in protecting plants from pathogens.
4/ because it allows the use of less [vermi]compost over a given area. There is nothing wrong with using only [vermi]compost instead of ACT if you have that much. ACT just allows you to use less [vermi]compost and it accelerates the microbial process.
*Note; I use the term bacteria/archaea because without complex testing it is not possible to visually tell the two apart. Recent research has revealed that archaea are commonly found in soil worldwide and have just as an important function in the microbial nutrient cycle as bacteria.
Recipes and Technique;
In case I have not been clear enough above, our goal in making ACT is to extract, multiply and grow mostly aerobic microorganisms in as large a diversity as possible and inclusive of three basic groups; bacteria/archaea, protozoa [flagellates & naked amoebae] and fungi. (Some [vermi]compost will contain rotifers which are extracted into ACT. These cycle nutrients in similar fashion to protozoa and are a bonus if present.)
Making ACT is not about putting in ingredients which directly benefit the plants. The foodstocks used are strictly to feed or benefit the microorganisms which in turn benefit the plants.
When I jumped on the compost tea bandwagon years back I utilized the whole gambit of ingredients recommended by the current (at that time) supposed authorities. These ingredients or foodstocks included, humic acid, kelp meal, black strap molasses, baby oatmeal (oat flour), fish hydrolysate, alfalfa meal, etc. We used variations of these ingredients in our 1200 gallon ACT maker on our farm and microscopic observation showed success.
I also experimented with using some rock/clay powders as ingredients and observed differences in the microbial make up which had positive results applied to the soil and plants. The types used were mostly soft rock phosphate and pyrophyllite.
Along the line somewhere we left humic acid out of a brew and noticed an increase in microbial numbers so we stopped using it ourselves but, possibly irresponsibly, I continued to recommend it because the ‘bigwigs’ did so. It was not until I devised a method to test each foodstock independently that I began to change my tune and begin to go against the grain of the contemporary experts.
By testing some ingredients independently in a liquid I observed;
1/ that humic acid in varying dilutions does not feed any sort of microscopically visible microbe. I observed that it actually suppresses microbial division and growth. This was confirmed by joint testing with Keep It Simple Inc. (KIS) in the Seattle area. We tested two of the most effective and popular brands. I cannot say definitively that all brands of humic acid will have similar suppressive effects in a liquid (ACT) but it is enough for me to discontinue using it or recommending it as an ACT foodstock. Please note that this does not mean that it is not good to use on/in soil….just not ACT.
2/ that kelp meal initially delays all microbial development in a liquid but does feed fungi and bacteria/archaea following 24 hours. If too much is used the effects are suppressive. From this I garnered that it should be used very sparingly and one must be prepared to brew a little longer if using this foodstock. Again, this does not mean that kelp meal is not a good thing to use in/on soil. It definitely is!
3/ black strap molasses (BSM) feeds both bacteria/archaea and fungi equally well contrary to what the A(A)CT aficionados were saying. The story was that BSM feeds only bacteria. This led to all sorts of misconceptions, even including ones made by USDA and Canada Agriculture scientists who declared that using molasses in ACT could lead to e-coli contamination. It is utter nonsense. Besides the testing I have done and ratifying assays carried out by KIS, it is common knowledge amongst many mycologists like Paul Stamets that BSM grows out fungal hyphae just fine.
4/ fish hydrolysate feeds both fungi and bacteria/archaea again contrary to the story at the time that it is mainly a fungal food. (I’m glad to see that story has now changed)
5/ alfalfa meal is also a decent all round foodstock which sometimes introduces protozoa cysts to the ACT. KIS has done more testing on this than I have.
The result of all this is that my attitude towards recipes for ACT has really evolved over the years with a trend towards the more simple. I know that there are a lot of people who place importance on creating a bacterial or fungal dominant ACT. At one time I myself was so influenced, however, the more I’ve learned and unlearned about living soil and a functioning microbial population interacting with plants, the more I’ve been led to allow the soil and plants to decide which microbes are actively needed by the rhizosphere team. What this means is that 9 times out of 10 I’m trying to create a balanced ACT with a decent ratio of the three basic microbial groups. When this hits the soil, some will go dormant to wake up later and some will be immediately put into action at the direction of the needs of the soil and plants.
The exceptions to this may be if I am attempting to battle a particular pathogen and want to attack it with a heavy fungal or bacterial (or a combo) ACT. In these situations some tweaking of recipes and timing can be helpful. If attempting these variations, a microscope is really the only way to confirm the desired microbial population. I have outlined some recipes which may trend towards a certain microbial group (or combo) or may assist with certain pathogens.
