Hello there! I have a geeky question.

I pot all my cacti and succulents in my own version of gritty mix. I use about 70% pumice and crushed coral (it comes in sacks from our garden center, all mixed together) and 30% garden soil.

My plants have been growing alright, I suppose.. Never thought twice about my potting mix because I know it's fast draining, the way I want it.

However I read something in another forum about how crushed corals make soil alkaline?? Something like that? So of course I googled 'so what if soil is alkaline' and I got nervous because apparently that's not good at all for cacti and succulents. It can even be "deadly" according to one blog.

SOOOO.. enlighten me, cactus experts.. Does the chemistry of my soil matter that much? Am I dooming my plants due to the large percentage of crushed corals in the mix? My pots are small, usually 4 inch ones.. I don't feed my plants so don't have to worry about that part of the chemistry equation..

I don't have a PH reader or meter or whatever people use.. Should I do those DIY vinegar tests on my potting mix?

Thanks for your time.