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Asked by justkaloog ·May 28, 2024 ·7.89k readers

Anaerobic decomposition?

I'm relatively new to organic/sustainable farming.  I have often been warned by other gardeners about the dangers of anaerobic decomposition/composting.  I even have had some experience where I believe I damaged some plants with a compost tea that went anaerobic because I stored it too long. KNF, particularly FPJ, appears to be entirely created through anaerobic decomposition. Perhaps you can shed some light on the mechanics behind anaerobic decomposition, why it is safe in some applications, including FPJ, but potentially harmful in others?

fermented-plant-juice fpj

Top answer

From the KNF library

From the KNF library Drafted by Claude from Office Hours and the books · Sep 2026 · 5 sources

Drake's library shows how KNF inputs handle gas, time and spoilage. It does not call FPJ anaerobic or aerobic.

The UH manual says to secure a breathable cover over the container (Student's Manual, Basic Course, p. 34). The microbes stay alive and keep making gas, so the lid stays loose (Student's Manual, Basic Course, p. 34). Ferment no longer than 7 days, since quality appears to diminish after that (Student's Manual, Basic Course, p. 34). For long-term storage, add brown sugar by weight to prevent souring (Student's Manual, Basic Course, p. 34).

Anaerobic is not always the enemy. Silage is packed tight to force out air, so it ferments anaerobically with lactobacillus instead of spoiling aerobically (Office Hours May 2025, 34:02). Lactic acid bacteria (LAB) are conditionally anaerobic and can also survive with oxygen (Cho, Recipe, p. 53). Cho writes that almost all LAB are anaerobic species (Cho, Theory, p. 81).

Too much moisture can push a system anaerobic in unwanted ways. In IMO collection, wet leaf mould forms an anaerobic condition (Cho, Recipe, p. 11). Smell is the test for a stored LAB culture.

The library says nothing about compost tea, or why it turns harmful when stored too long.

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