Question: Best color of volcanic stone to sow and grow up cactus and other succulents

[yonnoy]

Hello,

Do you know which are the best color of volcanic stone to to sow and grow up cactus and other succulents?
I have seen black, red, orange, yellow, white (pumice), buy I do not know which are good or bad.

[Steve-0]

I'm still new at this myself. In fact it was the question of "best soil for cactus" that brought me here.

That said....I can attest that black lava is going to absorb and radiate much more heat than the lighter color volcanic substrates.

Pumice would be my choice if I could get it cheap locally. I can...actually...the nearest volcano has squirted out tons of it. Problem is 3 hour drive and then reducing said tonnage into gravel sized pieces.

So I'm using red lava for "big bits", then pea gravel sourced locally and final mineral is "ant mound fines" from local red ant mined out of the ground and piled up above their colony. There is a little amount of soil and peat with my mix which is by no means a "one size fits all" cactus soil.

Perlite is the "evil" choice of volcanic substrate that I'm using. Hate the stuff...it's puffed volcanic stone. Blows everywhere, floats like styrofoam...and its brite white = yuck. YMMV

Hope this helps some.

Steve

[Shane]

When I was buying pumice, I asked if the one I chose was more expensive because it was "nicer" than the other color. The salesperson helpfully pointed out that it's a matter of personal taste (and they're all the same price)

I think to answer your question it's a matter of style and they all work equally well. Darker colors might get a bit warmer, but it's not as much as you'd think. Light colored volcanic rock is still pretty dark, and they likely all absorb IR and UV light equally, minimizing any difference in visible light absorption

And as Steve says, perlite is pumice's evil twin. Some people like it, but to me it's just a real pain. (It's helpful up to about 10-15% in a soil mix, beyond that is when it gets nasty)