C. 3c. Long-Brewing Compost Tea

Compost teas that start aerobic, move into the anaerobic ranges, and because they are brewed long enough, return to aerobic fall into this category. They contain aerobic bacteria, and put-to-sleep anaerobic bacteria. Beneficial fungi, protozoa and nematodes have been pretty much destroyed by the anaerobic phase, although if the brew didn’t actually go anaerobic, then the beneficials may still be present.

These brews may contain some remnant anaerobic smells and materials. The diversity of food resources has clearly been increased, but the question remains what bacteria exactly were grown? Beneficials, or detrimentals? Disease-suppressors, or disease?

Disease-causing organisms often prefer, and grow better, in reduced oxygen condition. But if the brew went quite anaerobic, then the diseases were killed too. How low is low enough? When do the “bad guys” die, and when do the really bad guys, like Clostridium botulinum, start to grow? We don’t know.

What mix of foods results in the fermentative bacteria or fungi winning, versus the human pathogens? Is stirring vigorously at 12, or 16 hours going to select for the good guys enough to maintain the good guys? Or do you need to stir at 8, 12 and 24 hours? No one really knows. (If you do, please let me know, I’d like to see your data).

Most Biodynamic brews fit this LBCT definition, except Biodynamic preps do not always use compost. The preparations are plant teas, which means plant material is placed into water, stirred and the biology on the leaf surfaces grows using the sugars, proteins, carbohydrates, cellulose, and more recalcitrant (hard-to-decompose, quite complex and thus hard to attack) kinds of substrates.

Does that mean plant teas have no benefit? Of course NOT. If beneficial organisms are on the plant surfaces (and usually roots are included in the plant teas), the beneficial organisms will grow and increase in numbers or biomass during the brew cycle. Which good guys? It depends on the same factors as actively aerated compost depends – temperature, mixing, aeration, foods added, the age and stage of the plant (and therefore the actual foods added), etc.

But, in these LBCTs, no aeration other than occasional stirring is added. That means, if there are organisms present on the plant material, or in the compost if this is truly compost tea, the brew is very likely to go anaerobic for some period of time.

But for how long? And how low did oxygen go? And when did the growing organisms begin to run out of food, so that their oxygen use rate slowed? When did their metabolism slow down enough that oxygen began to diffuse back into the water faster than the organisms were using the oxygen?

By the end of a LBCT brew, the tea should no longer stink in any way, which means the tea has returned to the aerobic condition. The things that may kill your plant have been re-cycled back into bacteria biomass. Sorry, no fungi left in a brew that went anaerobic. The beneficial fungi are, for the most part, aerobic.

The time, or the conditions to allow conversion from aerobic to anaerobic and back again are not documented at all for these kinds of teas. That means that sometimes positive effects have been observed using these kinds of teas, but other times the teas have had no observable effect, and sometimes these teas kill plants. I’ve killed quite a number of plants using anaerobically produced tea, and while I have not published this data (it is hard to publish negative results), lack of publication does not mean it doesn’t happen.

That is why compost tea has been regarded as witchcraft, or voo-doo, or snake oil for all these years. The results have been too variable to make sense of what is going on. When sometimes great results occur, sometimes nothing, and sometimes really bad things happen, no one is inclined to put much trust in the results.

But, the Biodynamic approach controls many of the factors involved in tea making, IF THE PRACTIONER PAYS ATTENTION TO WHAT STEINER SAID. I’ve watched a number of biodynamic brews being made where part, or just about all of Steiner’s advice was ignored. If people don’t understand WHY something was required by science, they may ignore it. But then typically the results aren’t what you would want, or they do not give you the benefit you should be able to get.

The bottom line is, we need to put more effort into understanding these types of tea. But for now, until the work is done, either do what Steiner said, exactly, or use AACT. We are really getting a handle on how to guarantee that AACT is consistent, and beneficial, each time. Without an oxygen probe, and the time to monitor properly, FCT and LBCT remain of questionable benefit.

< previous next >