# Cactus Rot
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Rot
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Rot occurs when cacti have been planted in poorly draining soil, been overwatered or left outside during cold temperatures. Both fungal and bacterial pathogens enter wounds made in the plant and cause the cactus to rot from the crown, stem or roots. Moist environments encourage germination and spread of the disease. If the cactus has been infected in the roots, you might see the disease start at the base of the plant. Eventually, the disease spreads from the base to the top of the plant. Diseased areas look black, slimy and watering.
Treatment
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Cut away all discolored or diseased areas from the cactus with a sharp knife. Dip the knife in a mixture of 70 percent denatured alcohol and 30 percent water to sterilize it. Clean the tool between cuts to avoid spreading the disease. When cutting into the cactus, cut into a healthy area of the plant. For example, if the plant is 6 centimeters tall and 2 centimeters has been infected, then remove 4 centimeters from the plant to ensure that you remove the entire infection. Dust the plant with sulfur powder to prevent the infection from spreading.
Potting
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Repot any cacti that has experienced rot problems with sterilized potting soil. Make your own potting soil by mixing compost, grit and sand in equal parts, as recommended by the Cactus and Succulent Society of San Jose. Lift the cactus out of the old potting soil and place inside the new pot. You may need thick gloves depending on your cactus. Add a thin layer of gravel on top of your potting soil to help prevent future rot problems.
Watering
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Prevent rot by watering your cactus once a week and only once a week, suggests the Cactus and Succulent Society of San Jose. Lift up the cactus container and water around the diameter of the pot with bottled water or rainwater; using tap water can lead to salt accumulation in the pot. Pour water until you see it drain from the drainage holes. By lifting up the container, you allow the water to run out or the draining holes. Replace the pot on a saucer that has a 1/2 inch layer of gravel to help with drainage.
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