About 5 years ago, Sheridan Cleland of MyPDFscripts wrote the below article on his blog. Soon after, the site disappeared. I wanted to keep the memory alive, because these practices by the studios have not changed. They have only become worse.
Cacti are one of my favorite types of plants to grow inside all year and outside in summer. Unfortunately, the ambient air tends to stay moist during most seasons, a condition which makes cacti unhappy. Cactus potting soil can enhance drainage, increase evaporation and provide the dry conditions that cacti favor.
Like cacti, succulents do best in dry conditions. When growing aloe vera plants, plant them in a cactus potting soil mix or a regular potting soil that has been amended with additional perlite or building sand. Also, make sure that the pot has plenty of drainage holes.