What Does it Take to Kill a Cactus?

Cacti Thrive With Neglect

• It is a common misconception that cacti do best when they're ignored. This is not the case, though it might seem that way to some people. Like any plant, cacti thrive when their environment is optimal for their growth. For the majority of cacti, this means hot, dry and sunny conditions are best. It just so happens that forgetful people are inclined to water cacti properly.

Proper Conditions

• Cacti do best in sandy soil, but not sand itself since it cannot hold nutrients for any length of time. The best soil mixes are made with two parts garden soil, two parts sand and one part peat. Cacti prefer to be watered heavily and allowed to dry out before being watered again. Watering like this encourages healthy root development. Bright light is best for most cacti. Wet conditions, poor drainage and low light are surefire ways to kill a cactus.

Watch the Weather

• Indoor and outdoor cacti alike have specific temperature ranges in which they function best. Cacti can suffer a variety of problems when the temperature fluctuates too much outside of their comfort zone. Cacti suffer from freeze damage and can die if left in freezing temperatures for an extended period. On the other side of the spectrum is sunburn -- caused by exposing an indoor grown plant to too much direct sunlight before it has acclimated to those kinds of conditions. Usually cacti do not die from sunburn, but it can weaken plants so much that diseases or pests can invade.

Diseases and Pests

• Indoor cacti are less likely than those living outdoors to have problems with diseases or pests, but the threat is always there. Cacti diseases, be they bacterial or fungal, generally begin as a small discolored spot on the surface of the cactus and progress outward, enveloping all or most of the cactus. In a short time, the cactus dies. Incorrect environmental conditions generally weaken cacti enough that pathogens can gain an upper hand. Insects do less damage, though scale and mites can possibly kill a cactus if it is already weakened.