Agree 100$. I reuse mine at maybe 25-30% with new and the worm bin gets the rootball's, and used soil sitting around also gets run through the worm bin.
This. Exactly this.
I have 4 or 5 totes, about 50 litres or 12 gallons each. After each harvest, I fill each to about 20% with the soil from my outdoor pots after harvest, and chuck in 100 or so earthworms. While I wait for next outdoor season, I throw in raw food scraps, banana peels, ground coffee, crushed egg shells, homemade garden compost, fresh foraged kelp, spent brewer's grain, horse shit, rabbit shit, chicken shit, black soldier fly frass, etc.
Basically anything organic that I can forage, or bum for free. I try to vary it a bit between tote containers, more shit in one, more kelp in another. And cardboard often as a top layer in all, pre-soaked for a day or two in 'stinky water' - dechlorinated water drum that I occasionally throw in a handful of manure, compost or leftover fertiliser teas.
No formal worm farm 'sticking to the rules', no separation or harvesting of castings.
The earthworms are happy, and reproduce, and recondition my soils between grows, supercharging it with microbes and macro and micro nutrients.
Two months before my next grow season, I mix all the containers into one heap so that they balance out, and add aeration amendments, and fill my pots.
I like to have the grow medium settled, so that the soil web has a chance to establish itself long before my plants go in.
Happy frog has a high percentage of sphagnum moss, which will start to break down after a few uses, making it very acidic.
Potash can help with the acidity, or activated charcoal ... but the charcoal needs to be 'innoculated' with nitrogen ... and even better if infused with microbes as well.
I typically add lime and water in Epsom throughout.
Lime would do much the same as potash to lower acidity ... but yes ... I add Epsom Salts as well.