[header] How to repot a cactus [title] Know when to repot. [step] For most cacti species, you will need to repot the plant once its roots begin to show through the drainage holes of your pot or once the crown of the cactus reaches the edge of the pot. [substeps] This will usually occur every two to four years. 
Repot your cactus during the dry season, usually in late winter or early spring. Roots may break during the process, and moisture can cause those broken roots to rot.