It’s common for people to think that cacti are indestructible. Also, it is true that they are extremely low-maintenance.
Cacti need very little water in order to survive, and too much water can actually kill a cactus.
Because of this, it’s pretty common for overeager plant lovers to overwater their cacti.
It’s important to recognize the signs of overwatering so that you know when to scale back the watering. Read on to figure out how to save your cactus.
Stop watering right away, and treat root rot if it has occurred. Drain excess water and move the plant somewhere with more sunlight and less humidity. Look for a planter and potting mix that optimize drainage.
Keep reading I’ll walk you through every possible solution caused by overwatering.
Is my cactus overwatered or underwatered?
It’s far more likely for a cactus to be overwatered than underwatered, but there are ways to check for both. One sign of an overwatered cactus is pale or brown leaves.
An underwatered cactus will often become dry, and the plant will wilt.
If the cactus is left unwatered for a long period of time, the roots can dry out and the plant will be unable to grow.
If you’re not sure whether your cactus needs more or less water, it’s better to err on the side of underwatering.
Since cacti are drought-tolerant, it’s easier for a cactus to recover from underwatering than overwatering.
Signs of Overwatered Cactus
Cacti are very low-maintenance, and they don’t require much watering. Cacti have adapted to the desert climate, which is why they can survive on such little water.
It’s possible to go overboard with watering, and many people end up killing their cactus with kindness. Here are some common indicators of overwatering:
Looks Can Be Deceiving
The first sign of overwatering is counter-intuitive. When overwatering your cactus, it will often plump up and grow, looking like it’s happy and healthy.
In reality, however, the roots are damaged, and the cactus will soon start to show the signs.
It’s important to check for the signs of overwatering early on. This is the point when you can slow down on the watering and have the highest chance of saving your cactus.
An overwatered cactus may turn a dull green color. Over time, your cactus might turn yellow in a process called Chlorosis.
This can cause stunted growth since the plant is no longer able to absorb nutrients from the soil.
Small Black Circular Spots
If you notice small circular spots on the cactus, this could be a sign of a fungal infection. Other symptoms to look out for include discolored scabs, soft areas, and sunken spots.
Fungi thrive in warm, moist conditions, and often result from overwatering.
Soft brown spots
Soft brown spots on the outside of the cactus are a symptom of root rot. Root rot occurs when the cactus is kept in waterlogged soil, and the roots begin to deteriorate.
As the roots die, the plant will not be able to take in as much water from the soil, which can cause the whole plant to die.
There are some other things you can check to determine if root rot has taken place.
Cactus experiencing root rot will often have an unpleasant rotten smell. Some people describe the smell as sulfurous or like compost.
The smell is a result of bacteria that grows somewhere without oxygen, like the bottom of a waterlogged pot.
If you’re worried about overwatering, it’s a good idea to check your plant’s roots for signs of rot. Healthy roots are white, whereas rotten roots will be brown or black, and will feel soggy.
Depending on how far the root rot has progressed, you may still be able to save the plant.
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How To Save An Overwatered Cactus
If you notice that the soil is soggy but you don’t see any signs of water stress, all you need to do is dry out the soil and prevent the plant from being overwatered again.
- If standing water has pooled up in the soil, drain it away.
- Don’t water again until the top one to two inches of soil is completely dry.
- Make sure that water has a way to drain out of the soil. Elevate the planter above a saucer that can catch excess water that flows through the drainage holes.
- If you can, create extra air space around the roots by using a pencil to poke small holes in the soil. This will help more oxygen get to the roots and will help the soil to dry more quickly.
- Place your cactus to a drier area of the house. If the cactus is near a humidifier, try moving it somewhere else.
- Move your cactus to an area that gets more sunlight. This will help the cactus to use up water more quickly. In general, cacti thrive in bright and sunny locations. It’s a good idea to position your cactus in front of a south-facing window so that it gets enough sunlight.
Revive The Damaged Cactus
Now, you need to assess the damage. If you notice that your cactus has signs of damage such as yellowing leaves or sudden excessive growth, you need to assess the severity of the damage.
Wrap the cactus in newspaper and tip it out of its container, and then carefully brush soil away from the roots.
If most of the roots are white, you’re in luck. The damage hasn’t progressed too far, and your cactus will have an easier time making a recovery.
In this case, you should nurse your cactus back to health, drain the soil, and then repot in new soil once the plant’s condition has stabilized.
- Cut off some leaves from the very top of the cactus. This will help the plant save energy and direct its resources to recovery.
- If the soil is extremely soggy, take the cactus out of the container and leave the roots to dry on some newspaper. Move the whole plant in one piece, and do your best not to disturb the roots.
- Use a fungicide on the soil. Fungi thrive in moist environments, so it’s a good idea to prevent it from developing.
- Avoid fertilizing your cactus until it has recovered.
You may find that after all this, the soil is still waterlogged. This could be a result of the type of soil or planter that you are using, in which case you will need to repot the plant.
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Repotting The Cactus
Select an unglazed clay or terracotta pot a bit bigger than the cactus.
Fill the pot with a loose potting mix. You can find potting mixes specifically meant for cacti in garden stores. Potting soils with coarse materials like perlite will help aerate the soil and improve drainage.
- Gently place the cactus in the new soil, being careful not to disturb the roots.
- Bury the cactus about one inch deep in the soil.
- Refill the pot with soil.
If the roots have turned brown or black, that’s a sign that root rot has occurred. You will need to cut away the damaged roots and encourage it to grow new ones. Here are the steps for doing this:
Treating Cactus Root Rot
- Use a sharp, sterilized knife to cut away the rotten parts of the roots. If any rotten bits are left behind, they may spread to the rest of the plant.
- Keep the cactus out of the soil and let it dry out for a few days until a scab develops on the parts that you cut.
- Once the scabs have dried out, you’re ready to repot. Follow the steps above to transplant the cactus to a clean pot filled with cactus potting mix.
If your cactus has a fungal infection, the steps will be different. Assess your cactus and look for symptoms of fungal infection, which include small discolored spots, mushy areas, and small sunken spots.
Treating a Fungal Infection
- Use a sterile knife to cut off the damaged tissue.
- Allow the hole to dry out. Don’t water the plant from above until the wound heals.
- If the fungus has infected the roots, you should remove the infected soil and repot the plant in a new potting mix. Make sure to wash the roots before replanting.
- You may not be able to save your cactus if the fungal infection has spread to the roots. If you are unable to save the whole plant, you can take a cutting and let it root, forming a whole new plant. Leave the cutting out for a few days until a callus form, and then propagate it into the new soil.
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When To Water After Transplanting Cactus
After you transplant a cactus, don’t water the plant for the first week after repotting. It’s very important to let the soil dry out before you water it again.
Otherwise, the cactus will continue to show signs of overwatering. Stick your finger one to two inches deep into the soil and feel for moisture. If the top layer is completely dry, you can begin watering again.
Once a week has passed after repotting, water your cactus infrequently until you see new growth begin to appear.
How Often To Water Cactus
To prevent overwatering, it’s important to water in moderation. Cacti are unique because they store water in their leaves and stems. This means that it’s easy to overwater them, so be careful.
There are many factors that can contribute to overwatering. Here are some ways to avoid overwatering:
Water When The Soil Is Dry
Always let the soil dry out between waterings. Allow the top one or two inches of soil to dry out completely before watering the cactus again. A general rule of thumb is to water once every 10 days.
It’s important that your cactus is never left in standing water. This causes the roots to become waterlogged and can lead to root rot. Ensure that your plant has good drainage, and empty the saucer if any water builds up.
Select A Pot With Good Drainage
While it may seem like a small detail, the type of container that you use has a big impact on your cactus’ health.
Unglazed ceramic pots are a great choice since they absorb moisture and help protect the plant from temperature changes.
Terracotta pots are another good option to go with since they absorb excess moisture and help prevent the soil from becoming waterlogged.
One drawback to ceramic and terracotta pots is that they aren’t transparent, which means that you cannot easily see whether there is excess water in the pot.
Plastic and fiberglass are not ideal materials for cacti since these materials don’t drain very easily.
You should avoid using a metal container since metal heats up quickly and can burn the cactus. Metal also doesn’t drain very effectively.
Whatever material you go for, make sure that the planter has drainage holes in the bottom.
It’s important to water the cactus until the water drains through the drainage holes since this helps flush out any salt in the soil.
Use a Small Container
When selecting a pot, go with the smallest size that you can. The cactus should be able to sit comfortably in the planter without much spare room.
A small container helps prevent the cactus from sitting in excess water. In a large pot, the water will take longer to evaporate, increasing the risk of root rot.
Use a Soil That Allows Water to Drain
Soil type is also very important. The soil needs to be able to drain well so that water can quickly make its way through the soil and to the drainage holes in the bottom of the pot.
Select a sandy, pebbly, and porous potting mix. The soil should also contain organic matter, which will moisturize the roots but will also dry out quickly.
Water According to Season
The season impacts the plant’s water needs. The seasons are different everywhere in the world.
So use this as a general guide and tailor your watering schedule to the temperature in your area and the needs of your cactus.
Cactus need less water in the winter because they usually stop growing when temperatures get cold.
Cold soil also stays moist because water doesn’t evaporate as easily. This means that you don’t need to water as often in colder temperatures.
In the winter, your cactus may only need to be watered once a month. However, each cactus is different.
The best way to know whether to water your cactus is to check the moisture of the soil.
One thing to keep in mind is that heaters may cause the plant to dry out. To avoid this, put a tray of water near the cactus or use a humidifier.
In the spring, cacti liven back up after a period of dormancy. You’ll need to water your cactus more frequently around this time, about once a week.
In the heat, plants lose more water due to transpiration. Water your cactus two or three times a week over the summer to compensate for the water loss.
Temperatures can fluctuate in the fall, so keep an eye on the soil’s moisture levels. As a general rule of thumb, aim to water about once a week in the fall.
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Water According to the Age of the Cactus
Cacti need different amounts of water over the course of their lives. Young cacti need more water than older ones since they are still growing.
Large, older cacti have a smaller surface area relative to their volume.
This means that less water evaporates from the plant’s surface relative to the amount of water that it takes in.
As a result, larger cacti do not need as much water as smaller ones.
Source: Texas A&M University
Common Mistakes in Watering Cactus
Here are some common mistakes that people often make when taking care of a cactus.
As you know, cacti are highly sensitive to overwatering. Make sure to let the top few inches of soil dry out completely between waterings.
Water your cactus as infrequently as possible, and your plant will thank you.
Choosing the Incorrect Soil Type
If the soil is too tightly compacted, water will not be able to drain through. This can cause the plant to become waterlogged, which can lead to root rot.
Compacted soil also prevents nutrients from reaching the plant’s roots, which can lead to nutrient deficiencies.
Choose a potting mix that is sandy, pebbly, and porous. This type of soil will allow water to drain freely through the soil and help prevent overwatering.
Using a Pot with Poor Drainage
The type of pot you select also influences drainage. Containers made of non-porous materials like plastic and metal are not ideal for cacti. Instead, select a planter made of unglazed ceramic or terracotta.
Not Changing Watering Frequency with The Seasons
As the temperature changes, so too do your plant’s watering needs. Your cactus will grow during warmer seasons and will need more water to help it thrive.
When the weather gets colder, your cactus will not need as much water. Make sure to adjust your watering schedule to account for temperature changes, so that you don’t give it too much water.
How Do You Revive A Dying Cactus?
With proper care, you can revive your dying cactus. If you notice that your cactus is overwatered, it’s important to scale back your watering schedule and allow the soil to dry out completely.
There are many steps that you can take to prevent overwatering. Choosing the correct potting materials, allowing for drainage, and paying close attention to your cactus’ needs are key.
What do you do to keep your cactus happy and healthy? Let me by leaving a comment below.