If you’re finding a way to make compost tea without a pump, think again! A supposedly useful compost tea made without needed aeration can turn into the harmful element. How? We’ll brief you in this article.
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Anaerobic vs Aerobic
Aerobic – requiring air, specifically oxygen, in order to remain active. Aerobic organisms require between 6 and 8 mg of oxygen per ml of tea in order to continue growing.
Anaerobic is the opposite of aerobic and means lacking oxygen. When oxygen falls below 6 mg per ml, facultative anaerobes will begin to convert their metabolism to anaerobic metabolism, producing alcohol, highly acidic organic acids, and other metabolites that can be toxic for aerobic organisms such as plants.
As oxygen concentration drops below 2 to 4 mg per ml, strict anaerobes begin to grow, producing materials that are ever more detrimental-to-plants.
Brewing Process of Compost Tea
The aeration condition of your brewing process has a direct effect on the bacteria. Although very small, over 600 million bacteria are present in one teaspoon (gram) of healthy soil.
Most soil bacteria are beneficial and help plants grow in a variety of ways. Bacteria help retain nutrients in your soils, so you don’t need expensive fertilizer additions. They also help build soil microaggregates, which are the first building block for making good soil structure.
Compost tea is a living solution made through growing beneficial soil micro-organisms by aerating water in the having compost and organic microbe foods.
So compost tea gives a new life to your soil by bringing a lot of benefits that are described in detail in this post.
So why is aerating Compost Tea important?
If you have kept an aquarium in your home ever, you know how important is aerating the water for fish to breathe. Similarly, we are aerating the water for aerobic microbes to breathe. The harmful microbes thrive in low oxygen conditions as we have described above in some details. A variety of microbes at varying concentrations are present in compost tea. Aeration is said to increase the concentration of beneficial ones.
Cons of Non-Aerated Compost Tea
The anaerobic process produces a very acidic environment that reduces the pH to as low as 4. The byproduct of anaerobic is methane that is more harmful than Co2, a by-product of the aerobic process. It takes more time to brew the tea with no aeration. The anaerobic compost tea stinks as it emits smelly gas as a byproduct and has incomplete decomposing residue. The weed seeds and pathogens aren’t destroyed as anaerobic doesn’t produce enough heat. Also without bubbling the water, you’re inviting the mosquitoes to thrive in stagnant brewing tea water.
With all these cons, the application of anaerobic compost tea does not make your soil anaerobic. The causes of Anaerobic soil include poor drainage, soil compaction, overwatering, or high clay content.
However, some research has also shown that non-aerated compost teas may be useful in suppressing some pathogens on a few plants.
Detect Anaerobic Compost Tea
Anaerobic metabolites “stink”. Your nose is good at detecting anaerobic odors that include
- the rotten egg odor (hydrogen sulfide production, which means loss of fertility as well)
- Ammonia (smells like urine, or an outhouse and also means your nitrogen is heading into the atmosphere, and you are losing plant production.)
- Vinegar, sour milk, vomit, putrefaction, etc., odors.
Causes of anaerobic Compost tea
The bacteria and fungi gain footholds form a film of living biomass on the surface of any material. Bacteria make slime materials that glue them to those surfaces. No matter how humans might try to make surfaces that bacteria can’t glue themselves onto, we have not been successful at doing that, nor would we want to! Bacteria thus start the decomposition process of nearly any material, but then the fungi land on the surface and start to etch into the material with the powerful enzymes they make, wrapping around and within the film of bacteria. Once the bacteria and fungi attach, protozoa, nematodes, tiny microarthropods, and other things begin to live within the bacterial and fungal “housing project”.
Bio-films can have so many active or organisms in them that any oxygen present is used up, and the material often becomes anaerobic. The critical factor is how active are the organisms, and how rapidly is oxygen diffusing, into the material. If oxygen use is more rapid than oxygen diffusion, the material will become anaerobic and all those nasty, stinky anaerobic decomposition products will be made (see above for a definition of anaerobic).
In tea-making machines, it is critical to prevent anaerobic bio-films from forming, or the beneficial organisms in the tea will be killed. Aeration has to be great enough in all parts of the machine so that if a film forms, it stays aerobic. Cleaning the tea machine is important as well then to prevent the buildup of biofilms.
