Here’s what you want in a succulent and cactus mix.
This applies to whether you’re growing them indoors or outdoors. 1) The mix needs to have excellent drainage. 2) It important to be well aerated. 3) It needs to be soil-less. Regular garden soil is way too heavy. 4) Which leads us to: it needs to be light.
The roots, stems and leaves of succulents and cacti all store water and can easily succumb to root rot. The roots need oxygen and a mix which is light, well aerated, drains well and is soilless helps to prevent overwatering.
You can make your own succulent and cactus mix, buy it online or at your local garden center. When I lived in Santa Barbara, I would usually buy my mix from the California Cactus Center as they formulated their own. Here in Tucson, I stated buying Tank’s which is also a local mix.