I live in the city of Riverside California which is in Southern California. Wikipedia shows the climate to be semi arid bordering on arid (we may have crossed the border). I just purchased 2 species of unknown Lithops that will live outside in pots. I have read the vendors suggestions and searched the internet for information about the proper soil mix. A few of the suggestions were for a mix that was just small rough pebbles with little or no organic material.
Is the commercial cactus and succulent mix that I use for my cacti appropriate for Lithops (and 'split rock') or do I need to add inorganic material and if so, what?