What Causes a Cactus to Die?

Sunburn

• Cactus plants like sunlight. When you bring a new plant into the home, it needs a bright window where it has indirect sunlight most of the day. Placing the cactus indirect sunlight or moving it outdoors to a sunny patio during the summer months may sunburn the plant. If you place the plant outdoors, slowly introduce it to the sun. Place the plant where it has two to three hours of sun and shade for the rest of the day. In two to three weeks, the plant is accustomed to full sun.

Water

• Cactus plants need water, but overwatering causes the roots to rot. Cactus plants grown inside need water about once a month or when the soil is dry. Plants grown outdoors in direct sunlight need water one or two times a week.

Planting

• Incorrect planting depths can kill a cactus. Cactus plants are not identical, even of the same variety. Cactus such as the prickly pear plant needs planting no deeper than 1/2 the depth of the plant's lowest pad. Plants such as the saguaro and other columnar cacti need planting so that the green stem tissue is not buried in the soil.

Soil and Container

• The soil kills cactus if it doesn't have good-drainage. Soils retaining too much moisture kill cacti. A good soil for cactus is one part course fill, one part washed sand and one part potting soil, but not garden soil. Containers need drainage holes on the bottom so excess water drains.

Crown Rot

• Cactus plants are susceptible to crown rot and bacteria necrosis of saguaro. Crown rot is a fungal pathogen with spores that become airborne during watering or on windy days. Sunken, dark areas appear on the top of the plant, and the cactus appears to be dying. Cactus plants with crown rot eventually die and should be discarded before infecting other plants.