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Your cactus has a hole in it because of pests, physical damage, or a fungal infection that has created an entry point.
If you’ve been asking why does my cactus have a hole in it, you’re not alone, it’s a common issue for indoor and outdoor plant lovers alike.
A hole in your cactus is never a natural part of healthy growth, so it’s a sign that something has bored into the flesh or that damage has opened up a wound.
In this post, we’ll explore the most common reasons why a cactus gets a hole, how to identify the culprit, and what you can do to treat and prevent it.
Let’s dig into the mystery of that hole in your cactus and get your plant back on track.
Why Does My Cactus Have a Hole in It? The Main Culprits
The quick answer to why does my cactus have a hole in it is usually pest activity, but there are a few other possibilities worth knowing.
Cactus holes don’t just appear overnight, so observing the size, shape, and location can tell you a lot about the cause.
Here are the most common reasons your cactus has a hole, broken down by what you might be dealing with.
1. Pests Like Cactus Borers and Weevils
The number one reason why does my cactus have a hole in it is boring insects, especially cactus borers and weevils.
These pests lay eggs on the cactus skin, and when the larvae hatch, they burrow straight into the flesh.
You’ll often see a small, round hole that looks perfectly drilled, sometimes with frass (insect droppings) around the opening.
If you notice a hole in your cactus and tiny sawdust-like material near it, you’re almost certainly dealing with borers.
Treatment involves removing the larvae if possible and applying an insecticide designed for cactus pests.
Check your cactus regularly, because a single borer can create multiple holes as it tunnels through the plant.
2. Physical Damage That Turns Into a Hole
Sometimes a hole in your cactus comes from physical injury, like a scratch, a bump, or a knife cut during transplanting.
While the initial wound may be just a gash, it can become a hole as the cactus heals and the damaged tissue shrinks or rots away.
If you’ve recently moved your cactus, dropped something on it, or even brushed against it with gardening tools, that’s a likely culprit.
A superficial wound shouldn’t worry you much, but it can invite infection, so keep an eye on it.
The hole may look dry and calloused if it’s healing well, whereas a wet, mushy hole suggests rot is developing.
3. Fungal or Bacterial Rot Creating Cavities
Another reason why does my cactus have a hole in it is rot, which can eat away at the inner tissue and leave a hollow cavity.
Overwatering is the usual trigger, because it weakens the cactus and allows fungi or bacteria to take hold.
You might notice the hole is accompanied by discoloration, a soft texture, or a foul smell coming from the plant.
Rot holes tend to be irregular and wet, unlike the clean, round holes made by pests.
If the rot is severe, you’ll need to cut away all affected flesh and let the cactus dry out completely.
Prevention is easier than cure here, so always use well-draining soil and water only when the soil is bone dry.
4. Sunburn or Cold Damage Leading to Tissue Collapse
Extreme temperatures can cause cactus tissue to break down, and that collapse can look like a hole in your cactus.
Sunburn, in particular, causes the outer skin to blister and peel, leaving a sunken area that may eventually form a hole.
Cold damage does something similar, turning flesh mushy before it dries out and falls away.
If you’ve recently moved your cactus to a brighter spot or left it outside during a frost, that’s a strong clue.
The hole from temperature stress is usually shallow and dry, but it can deepen if secondary infections occur.
How to Tell What Caused the Hole in Your Cactus
Once you notice a hole, the next step is diagnosis before you try any treatment.
Here’s how to narrow down the cause based on visual clues and a few simple tests.
Check the Hole’s Shape and Edges
A perfectly round, smooth hole is almost always from a boring insect, while an irregular, jagged hole points to physical damage or rot.
Use a magnifying glass to inspect the edges for tiny eggs, webbing, or frass, which confirm pest activity.
If the edges are dry and calloused, the hole is likely old and healing; if they’re wet or mushy, you’re dealing with active rot.
Look for Other Symptoms on the Cactus
Does the cactus show yellowing, soft spots, or a sticky residue? That suggests pests or disease, not simple trauma.
Multiple holes in a pattern, for instance, are a classic sign of weevils, while a single hole near the base often indicates borers.
Rot-related holes are usually accompanied by a change in color and a wrinkled, deflated appearance.
Take a mental snapshot of your watering schedule and recent environmental changes, because that history is a huge clue.
Gently Probe the Hole
Use a sterile toothpick or thin skewer to gently touch the inside of the hole.
If the tip comes out dry and clean, the hole is superficial and likely healed.
If the tip is wet, dark, or smells bad, you have rot that needs immediate attention.
And if you see movement or a small worm-like creature, you’ve found your pest and you can remove it directly.
Just be gentle, because you don’t want to widen the hole or introduce new bacteria.
How to Fix a Cactus With a Hole
Now that you know why does my cactus have a hole in it, let’s talk about the fix, which depends on the cause.
Here’s a step-by-step approach to treating your cactus and helping it recover.
1. Remove Pests Immediately
If you see borers or weevils, your first job is to get them out of the hole.
You can use tweezers to pull out visible larvae, then flush the hole with a mixture of water and a few drops of dish soap.
After flushing, treat the cactus with a systemic insecticide labeled for cactus, which will kill any hidden pests from the inside.
Repeat the treatment after a week to catch any newly hatched eggs.
2. Cut Away Rotten Tissue for Rot Holes
For rot, you need to act fast because it can spread throughout the entire cactus.
Use a sterilized knife to cut away all mushy, brown, or smelly tissue, making sure you go well past the visible rot into healthy green flesh.
Dust the cut area with sulfur powder or cinnamon to help it dry and prevent reinfection.
Then let the cactus sit in a dry, shaded area for several days so the wound can callous over.
Your cactus may lose a chunk of its body, but it can survive if the core and roots are healthy.
3. Let Physical Damage Heal Naturally
If the hole is from physical damage, the best treatment is often to do nothing but keep the cactus dry and clean.
Avoid watering until the wound has calloused, which can take a week or more.
Mist the area with a fungicide if you’re worried about infection, but otherwise leave it alone.
The cactus will form a corky scar over the hole, and that’s completely normal and harmless.
4. Adjust Your Care Routine to Prevent Further Holes
Once your cactus is stable, change your care habits so this doesn’t happen again.
Water less frequently, ensure your pot has drainage holes, and use a sandy, gritty soil mix.
Keep your cactus in a spot with good airflow and bright, indirect light, not harsh direct sun that can cause burns.
Inspect your cactus weekly for early signs of pests or damage, catching problems before they become a hole.
So, Why Does My Cactus Have a Hole in It? Final Thoughts
Your cactus has a hole in it because of pests, physical damage, or rot, and the cause determines your next move.
In most cases, a hole in your cactus is treatable, and your plant can go on to live a long, healthy life.
The key is doing a quick diagnosis, treating the underlying issue, and then adjusting your care to keep your cactus strong.
Now you know exactly why does my cactus have a hole in it and how to respond, so grab your supplies and get your cactus on the mend.
Your cactus will thank you with new growth, and you’ll never be caught off guard by a mysterious hole again.