ACT - Aerated Compost Tea

Okay, it seems the time has come to write a new thread on ACT which will help dispense with some of the myths. Perhaps it will be stickied.

I have very little time today so let me just begin with a few myths and I'll come back to this in a day or so. I'd appreciate it if the thread was left alone until I get a chance to complete the beginning.

Common Myths; [In no particular order]

1/ Small bubbles destroy fungal hyphae or other microbes.

This is utter nonsense. The bubbles/air would need to be super compressed to harm any microorganisms.

2/ Molasses should not be used or only feeds bacteria.

Black strap molasses (BSM) is a complex sugar/carbohydrate and feeds bacteria/archaea and fungi equally well.

3/ Fungal hyphae is difficult to grow in ACT.

If you have fungi in your [vermi]compost and have a decent brewer design and use 0.50% BSM it will grow out in the first 15 to 20 hours along with bacteria.

4/ You can have too much air/agitation in a compost tea maker.

This would only be true to the extreme...if your water was jumping out everywhere. If a salesperson is telling you microbes need gentle bubbling, they do not know what they are talking about.

5/ One can make good ACT with an aquarium pump in 5 gallons of water.

We did almost a year straight of research (at a cost of thousands of dollars) building almost every conceivable compost tea brewer design and size, ranging from 1 to 1200 gallons. These included every type itemized on my webpage in the design section and more. We measured the dissolved oxygen (DO2) religiously at all hours of day and night, eliminating configurations which failed to maintain the DO2 at or above 6 PPM. This is close to the minimum level required to support aerobic organisms.

The outcome of this research was, the estimation, that the minimum flow required from an air pump to make compost tea while maintaining the DO2 at 6 PPM, is 0.05 CFM per gallon while the optimum flow is 0.08 CFM per gallon or greater. (the only exception was when utilizing airlifts)

This means that most aquarium pumps will not work with a 5 gallon ACT maker, no matter what a couple of guys from Texas say. Two gallons, perhaps.

6/ Nematodes are a common microbe in ACT.

I’ve received many emails from folks distraught over the fact that they found no nematodes in their ACT or that they had very few. This is normal. Unless you happen to have a species of nematode which is an aquatic dweller, (rare in compost wouldn’t you think) you are very unlikely to have many surviving in ACT over 4 or 5 hours old. Why? Because they drown. A few will survive, which accounts for some making it to the end. Even companies which sell nematodes instruct customers to not leave them in the distribution water more than two hours.

I’m pretty sure that this myth originated with SFI but even they (Ingham) have now changed their tune and say ACT is not a good environment for nematodes.

7/ You can tell that your ACT is finished or ready to use when it forms a head of foam.

More bunk! But this does have a bit of foundational truth. Foam can be formed by proteins in the water created by microbial activity, however this is not a reliable indicator. Foam can also be created by saponins (aloe vera, alfalfa, yucca) or just by adding molasses or by worms which might have made it in there. I have examined very foamy ACT microscopically which was practically devoid of microbes and ACT with no foam at all which has been swarming with microbial activity.

The best bet to tell when ACT is finished is to use it between 24 and 40 hours, smell it to make sure it has not gone anaerobic (you’ll know) and that most of the foods you added have been consumed. It should smell earthy or somewhat like mushrooms.

I’m not sure how this myth got started but it sure took off.

 

Enough myths for now.

What is compost tea?

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. (see youtube below) 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 rhyzosphere. This works mainly because as the flagellates (protozoa) consume the *bacteria/archaea they utilize only 30 to 40% of the energy intake for their sustenance and the remaining 60 to 70% 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.

[ame=http://www.youtube.com/watch?v=Sgc0e8ed0dw&feature=plcp]Twelve Gallon Airlift Vortex Bioreactor - YouTube[/ame]

 

I'm not sure what I said may have led you to this conclusion. Over aerating would entail water not staying in the vessel....like almost emptying out.

 

I'll get to the recipes and techniques this weekend.

 

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 rhyzosphere 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.

Recipes;

Through a plethora of trial and error brewing with a dissolved oxygen meter at hand we determined that a pretty reliable volume of [vermi]compost to use is 2.38% by volume of water used up to around a 250 gallon brewer.

So if you have 5 gallons you multiply that by 2.38% to get the amount of [vermi]compost to use. Then you can go to; Online Conversion - Volume Conversion and convert it into any unit of measure which is convenient. In my opinion measuring [vermi]compost by weight is inaccurate because of varying moisture content.

Anyway to proceed we have;
5 x 2.38% = 0.119 of a gallon = 0.476 of a quart = 0.450 of a liter
= 450.5 milliliters [450 rounded] = 1.904 cups [2 cups rounded] - Your choice

Likewise with the use of black strap molasses, a percentage of 0.50% is a good median amount to use.

These two ingredients, perhaps surprisingly, comprise the total of inputs in most of our brews these days. This simple recipe, if using an efficient ACT maker and good quality [vermi]compost results in a microbial population made up of the important three groups. This is the only recipe used to date, in all the videos on my Youtube channel ‘Microbe Organics'

To get these three groups the ACT maker should be run for 36 to 42 hours. The ideal temperature range is 65 to 72 Fahrenheit (18 to 22 Celsius), however a little cooler or warmer is okay. I've had pretty equivalent results with ambient temperatures around 100 F (38 C) and as cool as 50 F (10 C).

To spill a small secret, [which I hope will not preclude you purchasing the related downloadable video on my webpage in the upcoming future, once I figure how to do it ] I've been pre-feeding or pre-activating [vermi]compost which is not so fresh by mixing in a small amount of wheat bran (livestock store or bulk foods department grocery store) and moistening with very diluted black strap molasses, loosely covered with cloth or paper towel 24 hours ahead of brew. (approximate ratios, wheat bran 1:30 [vermi]compost & BSM 1:300 water).

This has, so far resulted in attaining the desired microbial population at 24 hours brew time rather than the usual 36 to 42 hours.

Now for some of my other recipes;

A recipe for a balanced nutrient cycling ACT which many growers claim to have great success with is;

[vermi]compost – 2.38%

unsulphured pure black strap molasses - 0.50% [but you can use a maximum 0.75%]

fish hydrolysate (high quality) - 0.063%
Do not use chemically deodorized liquid fish!

kelp meal - 0.25% max. [Less is more!]
NOTE: This is a maximum amount of kelp and you can experiment using less. This is using regular grade kelp meal for livestock. If you have soluble kelp, I recommend using smaller amounts. As noted earlier kelp meal can initially delay bacterial multiplication and fungal growth in ACT.

soft rock phosphate granules/powder - 0.063% Consider this optional. In the past 2 years I've become more aware of the possibility of polonium 210 and lead content in soft rock phosphate which is radioactive. This varies depending on how it was mined and where. If you wish to use this in ACT check all available data. Look for heavy metal testing
We grind up the granules into a powder with a coffee grinder

The brew time should average around 36 hours and no longer than 48 hours. If you have a microscope then stop when the microbes desired are observed. Otherwise smell for the foodstocks being used up, possible rank odor (indicating anaerobes) and a positive earthy or mushroom-like aroma.

Fungal Brew;

If you want a brew which is more fungal increase the amount of fish hydrolysate to around 0.19% and you may wish to decrease the amount of molasses used so there is not a foodstock overload. Include a pinch [or handful, depending on brewer size] of alfalfa meal, not using more than 0.25%. It is important to not overload a brew with foodstocks, otherwise you can easily compromise the dissolved oxygen capacity of the unit.
>Most importantly discontinue brewing around 18 to 20 hours. Of course if you have a microscope you can judge that for yourself.
*Also, if you do not have fungi in your [vermi]compost, you won't have it magically appear in your ACT.

A Few Extras;

I sometimes include a pinch or handful [depending on brewer size] of sphagnum peatmoss in a brew. Depending on where the peatmoss was harvested, it will contribute a set of microbes somewhat similar to that derived from the ‘Alaska' humus or humisoil products on the market. It is a least a better bang for your buck and at best could be a trifle better quality-wise.

I've had inconsistent success battling powdery mildew by including soft rock phosphate and pyrophyllite clay powder, both at 0.063% in a 24 hour brew with horse manure fed vermicompost, BSM and fish hydrolysate. I have observed a peanut shaped bacteria/archaea in vast numbers with this recipe. In the ACT they are very active and appear to feed on yeast. This has led me to hypothesize that they ‘might' be devouring powdery mildew but at this point that is pure conjecture.

So that's it for today.