AVCT is supposed to help plants sprayed directly on foliage, provides a microbial environment that helps prevent disease, bugs, improve growth etc. Don't know about it mixing into the soil from the top. I imagine it's an undesired look? Since they are training pots I think it'd be alright, then mix some directly into the potting mixture when they get moved.

I wouldn't worry about it messing up your free draining soil, good castings are more in the nature of humus, simply adding organic matter that takes a very long time to physically break down, while supplying nutrients that the soil bacteria can convert for the plants - best to have it spread around just under the surface so it doesn't totally dry, and water leaching thru it is accessible to all the feeder roots

Bill

I'm new to this forum and came across this particular subject. When using vermicompost doesn't the castings retain water ? and if so would vermicompost be beneficial to Bonsai trees ? and how much would you calculate in usage ? I've read elsewhere that you shouldn't use vermicompost because your Bonsai will grow quickly and prove troublesome to care. HELP !

Here's a link to another forum's post that talks about VC and bonsai trees.

Enjoy! :)

Here is a link that might be useful: Bonsai & Vermicompost