How to Save a Rotten Cactus

This is a common problem with cactus and one of the main reasons they die.  There is good news in that just because it is rotting and dying, you can possibly save it. 

It just takes time and patience.  In this article, you will learn how to save a rotten cactus.

Cactus Rot

This condition can start anywhere on a cactus plant.  It can start from the top and spread down, start anywhere between the top and bottom, or from the bottom and go up.  To save your cactus from rotting, there are steps to take to fix it but which steps to use depends on where it is rotting.

Cactus Stem Rot

When this happens, it is generally mushy at the top.  This is referred to as cactus stem rot or tip rot.  This rot will spread quickly if you do nothing about it.  When it starts to rot, it will not stop and will continue to spread down the stem until the cactus dies.

There are several reasons why a cactus would start to rot at the top.  It can happen due to disease, water getting into an open wound on the cactus, or fungus.  When a cactus is damaged in any way, it makes it vulnerable to being infected with fungus spores or disease.  It may be hard to know exactly how it became damaged.  It could be bugs, it could have tipped over, something might have fallen on it, or even being brushed up against.

Stopping Cactus Rot Step by Step

Once you notice cactus rot, the first thing you need to do is prune it.  If you do not remove all of the cactus rot, it will continue to spread until the cactus is dead.  It spreads very fast.  How you save it will depend on where it has started to rot.  Cactus rot may start with some small brown spots but once you remove them, you will see that it is much worse on the inside.  

  1. The first thing to do is to choose your pruning tool, which can be pruning shears or a sharp knife.  If the cactus is thick, a sharp knife works best.  No matter which tool you use, you want to make sure that it is very sharp so you won’t crush the stems as you prune it.
  2. Make sure that whichever pruning tool you use that it is clean and sterile before you make any cuts.  This will help to prevent the spread of fungus spores and disease.  All you need to do is wash your pruning tools in hot soapy water and dry before using.  Some like to wash and dry them before they make each cut.
  3. In order to remove cactus rot and not kill the cactus, you need to do it in layers.  This will help to make sure that you are not missing any of the rot.  
  4. Continue to remove the rot layer by layer until all signs of the rot are gone.  As you work your way down the cactus, the layers of rot will get thinner.  Make sure that it is all gone because it can spread if any is left, no matter how small.  If the cactus is an outdoor plant, make the last cut at an angle so the water will not settle on top of the wound.  This can cause it to start to rot again.  If it can be moved, move it to a dry area so it is protected from the rain until the cactus has had a chance to callus over.
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After Pruning

Once you are done you will need to watch it to make sure that all the rot is gone and it is not continuing to rot.  If it starts to rot again, you will have to prune it again.  The wound should callus over after a couple of days and eventually, the area near the cut will start to send out new growth.


cactus rot

Cactus rot From the Bottom Up

If the cactus roots are rotted or it is rotting from the bottom up, there is not much you can do to say it.  The best thing you can do is cut off the healthy stem pieces and propagate the cuttings.  Prune your cactus back in layers as you would do in cactus rot to make sure that you have all the rot off of the healthy pieces of cuttings.  You will need to let the cutting dry for several days until the end that is cut has callused over.

Once this has happened, you need to dip the stem in rooting hormone and then put it in a soil mixture that is made specifically for cactus.  You cannot water it until you see new growth on the cutting.  This could take several weeks but it all depends on the variety of cactus you have.  

Cactus Facts

  • Black on top—this is because it has cactus tip rot.  It may also look brown.
  • Turning yellow—this is a sign your cactus is starting to rot.  You can save it using the steps listed but if it is all yellow, soft, and mushy you may not be able to save it.
  • If you have cactus bottom rot, it could be caused by overwatering.
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Keep reading: Coral Cactus (Eurphorbia Lactea Crest) Care & Growing Guide


Generally, cactus is a plant that is problem-free because all they need is sunlight with a minimal amount of care.  This will help them to grow healthy.  Their real enemy is getting too much water. In a home garden, overwatering is the primary cause of cactus rot.  If you know the signs of cactus rot and catch it before it becomes too advanced, then you can follow the mentioned steps to save it.  Look to see if the tip is brown or black and feels mushy.  If so, it may have cactus rot.  If you want your cactus to live, you have to get rid of all the rot or it will just start to rot again. Remember, if your cactus has rot, it is not always a death sentence.

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