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In the pictures above you can see my version of an Actively Aerated Compost Tea brewer which was based upon a design by Bruce Deuley which you can see HERE. The cat, Lane, was determined to help.
My design is slightly different in that I have only one bubbler in the bag with the compost and I made the hole at the top big enough to feed the bag through so it can hang from the lid itself.
When I brewed this batch of tea I used molasses for the bacteria and a small handful of brown rice flour for the fungi.
I set it all up to brew with the compost late in the evening, then in the morning I remove the bag of compost and continue brewing until that evening.
I use a watering can to spread a diluted solution of 3 parts rain water to 1 part compost tea until it is all used up. According to Bruce’s document, 5 gallons of compost tea should be enough to treat a full acre of land, so dilution is fine in those regards. It is important, however, to use the tea quickly and to not use fresh tap water for diluting the tea. If you need to use tap water let it sit over night or run the bubblers through it for a while to let the chlorine come out.
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Actively Aerated Compost Tea is not a method to distribute compost throughout the garden or putting the nutrients in a liquid form. Aerated compost tea is a method of growing the beneficial bacteria and fungi, present in healthy compost, to dense populations for seeding the garden with all this life.
Water is a good medium for these creatures to move around and reproduce in but it must have air pumped through it because the beneficial microbes need to breathe oxygen to live. If air was not added the water would be depleted of dissolved oxygen very quickly and the beneficials would give way to potentially harmful anaerobic bacteria.
By adding these microbes we are widening the base of the food web, increasing diversity and filling niches which may have otherwise been occupied by harmful bacteria or fungi.
There are many other sources that discuss compost teas in detail including Soil Foodweb, who everyone cites. They offer compost tea analysis to identify the quality of different teas. There are also many companies that are selling expensive brewers that do little more, if not less, than the brewer I made for less than $20.
Thank you for eliciting that the tea is inoculating more than fertilizing. I’m learning to use passive sun-fueled tea-making via clear or translucent containers with both submerged and floating type plants in them. The submerged plants, such as the fast-growing anacharis, put oxygen in the water, while the floating type plants such as the fast-growing duckweed or water hyacinth prevent mosquitoes. Also snails and fish where possible to mimic a pond. Rather than stirring I’d like to use gravity, e.g. via a spigot at the bottom.
Jim, that sounds pretty cool. It sounds similar to the justification of my Pond System. What is the end use for that type of tea and what do you think the benefits would be throughout the garden. Why do you prefer the water at the bottom?
It seems it would also be useful because it will attract insects and birds to the garden space to drink. The water hyacinth and duckweed can go so quick in my pond that they can be removed and added to the compost bin or straight to the garden where they will break down.