@Malcolm a link to a high quality and reasonably priced pumice General Pumice Products
Also check out Bonsai Jack, they have quality presifted components and mixes, prices are decent, also they can be found on Amazon. Bonsai Jack
@Malcolm @el_cheezer I use haydite currently in my mixes. It can either be a substitute for pumice or lava. Both are relatively neutral in pH, both have low/poor CEC, both are porous and serve as aeration and water reservoirs. Lava probably adds more trace minerals than pumice. I like the appearance of haydite better than pumice, but I use what is available locally and inexpensively.
@Ralph I also have used DE for several years in my mixes. I source mine from Napa it’s called Floor Dry or Oil Dry there and has a part #8822 affixed to it. I have had good success using this on many of my trees. The exception being azaleas, I’ve lost some really nice ones when I switched to DE. Others I know have had success with azaleas. DE definitely takes longer to scale down, notice I said “longer” and not doesn’t or never. It does scale but has taken 4+ years in most of my mixes or when added to a mix on an aggressively rooting species like bald cypress. DE is a good alternative, I like it. I also really, really, really like akadama. I have noticed all my trees do better with Akadama mixes.
I suspect its for several reasons. It holds water better and longer. DE tends to dry out more quickly and loses water to evaporation. I have used some soil test kits and Akadama also buffers soil pH better, it creates a more stable pH in the containers. Important if you have hard or alkaline water, as I do. I frequently have to use Miracid and other soil acidifiers and supplements for my more acid-loving species because of chlorosis. This has not happened with my Akadama mixes, I’m currently adding an venturi injector to acidify my outdoor tap.
@Malcolm I have mixes that Ive made for over a decade, to save on costs. Cough The reality is this… I spend considerable time sourcing material, I then spend TONS and TONS of time sifting and separating, I then have to mix the aggregates which also takes MORE time. I lose out on time with my trees and time I could spend on other things, and I still have some percentage of the aggregates that I “waste,” which are the fines that I amend the garden with. I’m soon to go with presifted and sorted aggregates, money well spent + time and frustration saved. That’s a WIN if you ask me.
Anyways, sorry for the long reply everyone. I’m going to attach a few more things here that might be of use for assisting you all in the soil conundrum.
American Bonsai Soil InfoAmerican Bonsai Soil Info they also sell mixes and individual components. More pricey than Bonsai Jack, nearly same quality.