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.
Plant aloe in a pot that contains at least one large drainage hole and is 2 to 3 inches larger in diameter than the base of the aloe plant. Use a soil mixture formulated for cactus, or combine equal parts potting soil and coarse sand to make your own mix.