So, this might be completely hairbrained, but here goes...

I used to brew my own Kombucha tea...full of beneficial bacteria, lots of micronutrients, etc...very easy to do in the warm garage....anyway, I'm wondering if there's a way to brew something for plants?

What if I had a starter source of microbes (like the "mother" when you brew kombucha) and grew it in a barrel of water with an air stone to oxygenate it?

Has anyone heard of it, and does it sound insane? I don't even know how to start Googling this....

Try Googling "compost tea" and "manure tea".

Some people get away without even aerating their "teapot", but an airstone would be a great way to encourage the aerobic microbes.

I think it is smart to use a compost heap as the source of the inoculum. Plus, perhaps, a little soil taken from 6" down in your very best raised bed.

Some people add a little molasses as a sugar source.