whats a good way to make your own cactus soil mix or i might say potting mix .
All the cacti and succulents I grow have done exceptionally well in a gritty mix of equal parts of screened pine bark, screened Turface MVP or Allsport and crushed granite (grower grit or #2 cherrystone). The shallower the container, the more difficult it is to get cacti and succulents to grow well.
Dehall, I use packaged Cactus soil, Perlite, and very coarse sand. If you can't find the sand, 'gritty, not beach/play sand,' bark will do.
The mix needs to be well-draining. Toni
I use the exact Gritty Mix tapla describes in his post. I use it for cacti and succulents, bulbs, many of my orchids, and most every other plant type I grow.
It's incredibly durable and lasts a long time, avoiding compaction through fast decomposition. It drains freely, avoiding any perched water. And it allows for the all-important exchange of oxygen and gases, to and from the root zone.
I try to avoid the commercially available potting mixes because most contain too large an amount of fine particulate.