How To Save a Cactus With Root Rot (A Complete Guide)


Are cacti your favorite gardening plant? Do you love the way they look and how easy it is to care for them?

If so, then we have some bad news.

Root rot can cause cacti to die or become stunted, which means that it’s important to know what root rot is and how to save cacti with root rot before they get too far gone!

This article will explain cacti root rot in detail, what can be done to treat it, and how to prevent cactus root rot from occurring in the future.

What is Root Rot?

Root rot is a condition of plants caused by a fungal infection.

This disease affects cacti and other desert plants. It starts by infecting the roots of a cactus plant, then spreads to the whole root system until it takes over your cactus.

The most common fungal cactus root rot is caused by the fungus Phytophthora cactorum. It destroys cacti from the inside out.

This fungus infects cacti by growing a mycelium that penetrates plant tissue and forms tiny spores.

These spores spread to other cactus plants through water or insects, which become carriers of this disease when they fly into another cactus garden.

Unfortunately, cacti are very susceptible to root diseases because their roots do not have many defense methods against infection. 

They absorb water from the soil, which helps pathogens travel up into their stems, causing illness or death.

What Does Root Rot Look Like in Cactus Plants

It is essential to know what cactus root rot looks like so that you can detect the problem in its early stages.

If it is left untreated, the rot will spread and kill your cactus plant.

The most common root rot symptoms include:

Cactus Stem Discoloration

When root rot is left untreated, cacti will show clear signs of cactus stem discoloration.

Cacti with root rot may begin to lose their bright green color and turn yellow or brownish.

Disintegrating Plant Tissue

Cacti that are affected by root rot often have disintegrating plant tissue because the roots become infected. This causes them to die off and expose the cactus core to air.

Once it has been exposed, it can quickly dry out, and dead tissue will fall away from the living part of your plant, leaving a hollow space within its central cavity.

Mushy Cactus Roots

Cacti with root rot will often have mushy cactus roots.

This is because as the cactus core becomes infected, it swells and starts to fill up the central cavity of your cactus plant, where its stem connects to its roots.

Eventually, this swelling can cause a rupture which allows soil particles, water, and bacteria into your cacti center causing further damage.

Soft or Discolored Spots on Cacti Stems

If you notice soft or discolored spots on any part of your cacti stem, then there may be a high chance that they are suffering from cactus root rot.

In many cases, these spots will also appear waxy, but if left untreated, rot can quickly spread to the cacti spines and cause them to lose their vibrant color.

Weak Cacti

Cacti that are suffering from cactus root rot will often lose their strength and become weak, which can cause them to fall over or collapse.

They will also become very difficult to hold up, and they may fall over even when cacti are watered properly.

Black Rot on Soil Surface

If you notice black spots of dead soil near the base of your cactus plant, then this is a sign that its roots have been infected by cactus root rot and may be dying off. This causes them to release their hold on the soil around them, causing it to decompose.

As they decompose, fungus such as molds begins to grow where the dead matter has settled at the base of your cactus or cacti.

Yellowing Cacti Spines

Cactus root rot can cause cacti to lose their vibrant color because it will often affect the cacti spines.

As the cactus becomes infected, these yellowing spots may also appear on its cactus spines located along its stem or any other part of your cacti plant.

Wilting Cacti Spikes and Buds

Another common symptom associated with root rot is wilting spikes and buds. If left untreated, this infection could spread internally through your entire plant, causing further damage.

You should be aware that once internal parts of a cactus become affected by root rot, they cannot be saved even if you treat external symptoms immediately before cactus stem discoloration becomes visible.

Internal Decay in Cacti

Due to changes within a cacti’s vascular system, this infection causes internal decay and an increase in respiratory activity resulting from cellular degradation.

At this stage of the disease, any attempts at treatment will be useless even if they are administered immediately after detection unless all affected roots have been removed before further damage has occurred.

As mentioned earlier, though, once the central cavity has been exposed, cacti with root rot will soon begin showing cactus stem discoloration.

What Causes Root Rot in Cactus Plants?

Root rot cactus is a severe problem. It’s challenging to treat, and if you leave it untreated, the cactus plant can eventually die.

The most common causes of root rot in cacti are:

Overwatering Cacti

The main cause of cactus and succulent root rot is overwatering.

Cacti and succulent plants generally prefer to be grown in very well-draining soil that remains dry for most of the time.

They usually don’t like having wet feet, so if you’ve recently given your cactus a big drink with lots of water, it may have developed cactus root rot.

An overwatered cactus can develop root rot within a few days.

Poor Drainage Conditions

Planting cacti in poor drainage conditions is the second most common cause of root rot.

If you’re growing cacti outdoors, make sure they are planted on hills or mounds to improve their drainage conditions.

A raised bed will also improve your cacti’s drainage condition if you don’t have space outdoors to create a hill or mound for them.

Over Fertilizing Cacti

While some fertilizers can be useful when it comes to helping your cacti grow faster and healthier, overfertilizing these plants can quickly lead to cactus rot.

This happens because all excess fertilizer gets left in the cactus soil and causes the cacti to become overwatered.

Unsuitable Soil Mixture for Cacti Plants

You must use a very well-draining cactus potting mix when it comes to planting cacti or succulents.

A commercial cactus potting mix is ideal because it contains pumice, lava rock, perlite, or sand which will help improve drainage conditions while still holding onto just enough moisture so your plants don’t dry out too quickly.

If you’re not using a commercially available cactus potting mix, you can create your own mix by combining equal parts of all-purpose sand, perlite, and peat moss.

Planting Cacti in Pots With No Drainage Holes

Another common cause of cactus root rot is planting cacti and succulents directly into decorative pots that don’t have drainage holes.

If you’re using a hanging basket to grow your cacti, make sure that the container comes with proper drainage holes or drill some yourself if it doesn’t already come equipped.

If you can see water accumulating on top of your cacti’s potting mix when drenching it every two weeks as outlined earlier on, this means there isn’t enough air getting to those roots, which could lead to infection and cactus rot.

How To Prevent Root Rot in Cactus Plants

Prevention is the best medicine for cactus root rot. Practicing proper cacti care is key to keeping a cactus healthy and avoiding root rot.

So if you want to keep cacti healthy and ensure that they don’t develop root rot, then make sure to do the following:

Water Cacti Properly

Cacti are desert plants, and they don’t need a lot of cactus water. Water cacti only once cactus soil is dry to the touch.

Ensure to water cacti cactus in the morning so that cactus roots have enough time to dry out before nightfall.

Make Sure To Repot Cacti Every So Often

If you want your cactus to remain healthy and not develop root rot, you should repot them every few years.

But make sure to use fresh soil when transplanting a cactus because cactus soil can carry cacti diseases, and old cactus soil might have cactus diseases in it that can be transmitted to cacti cactus.

Provide Cacti With Proper Sunlight

Cacti need sunlight to remain healthy and avoid root rot.

Ensure the cactus receives at least six hours of intense direct sunlight daily to photosynthesize properly.

If you want to keep cacti indoors, then make sure they receive sunlight through a window and not an artificial one.

Use a Well-Draining Soil

Cacti soil should be a well-draining one.

Cactus root rot starts when cacti become waterlogged and don’t have proper drainage for their roots.

Make sure to use sandy soil or add sand into your regular potting mix to better drain excess moisture from the cactus root zone.

Use a Pot With Proper Drainage Holes

Ensure that your pot has drainage holes in the bottom so that excess moisture can drain out.

If there are no drainage holes, you will have to drill some into it yourself or use a terra cotta flowerpot saucer designed for this purpose.

How To Treat Root Rot in Cactus Plants

The earlier you spot and treat this condition, the better your chances of saving your plant when it comes to root rot treatment.

If you catch cactus root rot early enough, there’s a good chance it will respond positively to treatment.

There are several ways to treat rotting roots. Below we will look at some of the most popular and effective ones.

Remove All Rotted Roots

Removing all the rotted roots is one of the most common and effective ways to treat root rot.

You should remove all rotted and soft parts of the roots. Be careful not to damage healthy roots while performing this procedure.

Cut Off All Affected Parts

If you notice that only certain areas are affected by root rot, you can cut off all the affected parts of your plant.

However, you should use sterilized tools to prevent spreading the infection further.

Replace Potting Soil With New One

An easy way to treat root rot is by replacing old potting soil with new fresh soil.

You will need a good-quality potting mix for this procedure.

Do not add fertilizer or other additives while preparing this mixture, as it may lead to additional problems later.

Let the Cactus Plant Dry Out

If your cactus plant suffers from root rot, it’s best to leave the soil dry for about a week.

This will help kill any pathogens or fungus present on its roots and slow down its growth rate.

Watering With Hydrogen Peroxide

One of the most effective ways to treat cactus root rot is by adding hydrogen peroxide (H202) solution to water when watering your plants.

Hydrogen peroxide kills fungi and other germs while promoting healthy tissue formation around the roots. It can be used alone or along with another treatment method.

Use Fungicides

Fungicides are available in both chemical and organic forms.

These products can effectively treat root rot, but you should carefully follow the instructions before using them to ensure that they won’t damage your plant or cause other problems.

Dip Roots In Baking Soda Solution

One of the least expected ways to treat cactus root rot is by dipping your roots in a baking soda solution made from one teaspoon of baking soda mixed with two gallons of water.

Apply this solution every week for about four weeks. Use fungicides along with this treatment method to increase your chances of success.

Use Beneficial Bacteria

Several species of bacteria can help in preventing and treating cactus root rot.

Bacillus subtilis, for example, produces enzymes that eliminate pathogens by breaking them down into less harmful substances.

These beneficial bacteria form colonies at the roots’ surface, where they release antibiotics to fight pathogenic fungi or other germs.

Caring For Your Cactus After Treatment

Once you have successfully treated your cactus plant, monitor its progress for several days or weeks until you are sure that there’s no chance of recurrence.

If everything goes well, then keep gradually increasing humidity levels to help the soil retain moisture longer while reducing watering frequency over time.

Make sure to water thoroughly, but never leave your plant sitting in a puddle of water.

Remember that preventing cactus root rot is easier than curing this condition.

Regularly check your plant’s roots for any sign of fungus or other ailments while carefully checking new plants before bringing them home.

Keep all infected areas clean and dry at all times, avoid overwatering your plants, use soil that drains well but still holds some water, and never use soil from outside as it may contain harmful contaminants or pathogens.

Final Thoughts

Cactus root rot can happen to anyone, even plant experts.

Your cacti should be fine if you can identify the problem before it gets out of hand.

However, if your cacti have been infected with root rot, do not hesitate to take action.

The sooner the problem is fixed, the better off your cacti will be in the long run.

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