Pocket Botanist
Check these first
- Press the base of the cactus to see if it feels soft.
- Check if the soil is damp deep down.
- Inspect the pot for drainage holes.
Likely causes
Overwatering
Most likelyHow to tell: The base of the cactus feels squishy or turns yellow and brown. The soil may smell musty or damp.
What to do: Stop watering immediately and let the soil dry out completely. If the rot is severe, remove the cactus from the pot, trim away any black or slimy roots, and repot in fresh, dry cactus soil.
Poor Drainage
PossibleHow to tell: Water sits in the bottom of the pot or the soil stays dark and damp for weeks. The pot lacks holes at the bottom.
What to do: Repot your cactus into a container with drainage holes. Use a gritty, well draining soil mix specifically designed for cacti.
Find out what's wrong with your cactus
The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.
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When to worry
If the stem is turning black or mushy, the rot may have already spread to the core. This is often fatal for the plant.
Stopping it coming back
Always wait until the soil is bone dry before watering, and never let your cactus sit in a saucer of standing water.
Cactus: root rot? Check yours with a photo
Every plant is a little different. Take a photo of your cactus and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.
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Or go to pocketbotanist.app/get on your phone
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Questions people ask
- Can I save a cactus with root rot?
- Yes, if you catch it early. Trim the rotted roots, let the plant dry for a few days, and repot in fresh, dry soil.
- How often should I water my cactus?
- Water every 14 to 30 days, but only when the soil is completely dry. In winter, you can water even less.
More problems with Cactus
This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.