Step 1. Step 1. Add succulent soil that is fast-draining to your pot. Add soil to the pot until it reaches the same area as before the rot. It can work but the roots must not be in direct contact with the water. This would cause root rot. Some, such as the cactus may be perfectly fine while others could cause serious health problems for cats. 1. Before you start digging it up, mark the north end of the cactus using chalk. If that is true for your forest cacti, begin with the same instructions as indoor plants.