Why Is My Cactus Turning White? 10 Reasons & Treatments

Cactus plants are exciting and low-maintenance plants that you can get used to with their varying shades of green adorned by spikes. However, when you notice their colors fading to white you naturally cause yourself to think “why is my cactus turning white?” 

The possible reasons why your cactus is turning white are:  

  • #1. Cacti exposed to cold
  • #2. Sunburned cacti 
  • #3. Cacti that have too little air ventilation
  • #4. Overfertilized cactus
  • #5. Overwatered or underwatered cactus
  • #6. Cactus that has been attacked by cactus moths
  • #7. Bug infestation
  • #8. Cactus exposed to chemicals
  • #9. Rotting cactus
  • #10. Fungal infections in cactus 

We shall go through all the possible causes and how to rectify them and restore your cactus back to its glorious green color! 

Grow vegetables in the garden? So, read this if you do: How To Prevent Cucumber Leaves From Turning Yellow?

#1. Cacti That Are Exposed To Cold

All cacti originate from warm climates, therefore they need the sun or at the very least, bright indirect light. So no surprise that they do not do well in areas with extreme cold like frosts and snow.  

Frost burn can affect some parts of your cactus, eventually making them start to turn white. Unfortunately even when rectified the plant cannot recover the areas that have been cold burnt. Your plant will be better off if you remove these parts and let the plant regrow.

What To Do

If you are living in a climate that is prone to frosts or snow you can bring your plant indoors. But, if you cannot do that, a sheltered spot or even a greenhouse will do. When you bring your cactus indoors, a sunny window ledge will be a good location.

But, if you live in a climate where the sun hardly peeps out during winter it might be a wise decision to invest in a grow light.

How To Prevent

  • Plant or place plants where they will be protected from snow or ice. For example by walls or window sills. 
  • Also, ensure that your cactus is not dehydrated, we tend to think that cacti do not need water when it is cold.
  • Cover any exposed roots with mulch or leaves if the plant is left outside.
  • As the days get colder, insulate the exterior of the plant’s pots with burlap or another type of insulating material.

#2. Cacti That Are Sunburnt

Sunburn is another factor that can make your cactus turn pale or even white. While some cacti may be able to take the heat some might find the sunlight too intense.

It is an excellent idea to do a little research before buying your cactus so as to ascertain which conditions are optimal for the plant, especially when it comes to sunlight exposure. 

What To Do

Give you cactus shade during the hottest part of the day. Or in case there are many cactus plants, it would be easier to have an area under shade cloth like a greenhouse. 

Also, other plants that are sensitive to heat can be put there too. If you live in a subtropical or tropical climate this is something you should invest in.

How To Prevent

  • If your cactus is getting sunburned you should take steps to rectify the situation before the damage is done as it may be irreversible. 
  • Make sure your plant gets light but not too much direct sunlight. 
  • Also, give enough water so that they do not dry out during extreme heat.

#3. Cacti That Have Too Little Ventilation

Cacti need air movement to maintain moisture in the plants and so cacti that are placed in an area with poor ventilation may start to lose color and turn white.

Furthermore, stagnant air can induce disease and even encourage pests. Furthermore, mold may start to grow if there is an excess of dampness, a situation brought about by poor airflow

What To Do 

If you can rectify the air circulation do so or move to a location with better air movement. Remove any mold, improve air circulation and reduce watering habits if necessary and your cactus will recover given time.

How To Prevent

  • Putting your plant in a well-ventilated area discourages mold. 
  • Water your plants regularly but not too often! 
  • Slow down watering if put in an area with poor air ventilation, and also decrease watering in winter. 

#4. Over Fertilized Cactus

If you are new to caring for cactus plants, their discoloration could be that you are overfeeding your cactus. While all plants now and again could do with some additional nutrients, overfeeding cacti could be catastrophic. 

Over-fertilizing causes the plant to stress, with the result being that parts of the plant begin to turn white!

What To Do    

Cut back the amount of fertilizer you are feeding. Give the plant some time to recover, and it will become green again.

You are actually only supposed to fertilize your plant once a year and that should be in spring. Most cacti species become dormant in winter so you should avoid feeding them at this particular time.

How To Prevent

  • To prevent overfertilizing your cactus, feed it only once a year at half-strength using a fertilizer formulated for cacti. 
  • You could also use a cactus mix for potting your cactus to provide it with nutrients.
  • Feed cactus plants only in spring and never in winter.

#5. Overwatered or Underwatered Cactus

Overwatering or underwatering both spell doom for the cactus plant! Let us have a look at the symptoms of both overwatering and underwatering.

Signs Of Overwatered CactusSigns Of Underwatered Cactus
Plant wiltingShriveling
Turns a black or brown colorYellowing
Mushy plant, soft stems, nasty smellBrittle roots
Rotting rootsSpines drying and brittle, drying leaves
Overwatered Cactus vs Underwatered Cactus Signs

What To Do For Overwatered Cactus?

For overwatered cacti, the best course of action is to hold off watering for a bit and allow the plant to dry out in a warm sunny location. Do not put your cactus in direct sun.

What To Do For Underwatered cactus

In the case of underwatered cactus plants, water them until the water runs out through the drainage holes at the bottom. After this leave the cactus for a few days before watering again.

Do the finger moisture test: Insert your finger into the cactus growing media, just an inch or two to test for moisture. If the top inch or two is dry you can water it again.

How To Prevent

  • Make sure that you are using appropriate containers for potting your cacti. 
  • They should have drainage holes on all sides of the pot, to facilitate water drainage. 
  • Also, your potting mix should be for cacti so that you don’t have a soil mix that is retaining too much water and suffocating the roots. 
  • Make sure you only water your cactus when they are dry!

#6. Cactus That Has Been Attacked by Cactus Moths

Your cacti turning white could also be due to Cactoblastis cactorum, which is a moth. After hatching out of the eggs, the larvae feed on the tissue of the cactus. This can lead to the cactus becoming deformed, white, or dead.

The moth could come about your plant by you buying a plant that is infected or passing on from one of your own infected plants. 

What To Do

There are two ways in which you can treat your plant:

Remedy 1

You can buy a Cactoblastis cactorum spray and use it to kill the moths as well as any larvae and eggs present.

Remedy 2

This treatment is for cactus plants with severe infestation. Cut off all infested parts of the cactus and get rid of them. The less food available for the moth larvae to eat, they will starve and will be unable to turn into adults.

How To Prevent

  • Avoid planting or keeping your cactus near any plants that may be attractive to the Cactoblastis cactorum like potatoes and tomatoes. 
  • You should also quarantine any new plants that you may buy, making sure to keep them away from your cactus for a while. 
  • You should also use an insecticide for any plants infested by bugs. 

#7. Pest infestation

Bugs such as aphids, spider mites, and mealybugs will also attack your cactus. The appearance of any white matter can be attributed to these unwelcome visitors. These pests lay their eggs in between the cactus needles, which hatch out into more pests.

The bugs then excrete a substance called honeydew on the cactus which encourages mold and rot, not to mention this substance invites ants too! 

What To Do 

If detected early an infestation can be averted, by starting the treatment. So. for you to avert such calamities you have to be vigilant and constantly be checking or examining the condition of your plants. 

You have to be on the lookout for any brown or black spots on the leaves. Or any yellowing of foliage should be taken as a sign as well. If you notice anything it could be the first sign that all is not well. 

Do a more thorough check, as be it a pest or disease it could spread onto your other plants. Also, you can spray the infected plant with neem oil or insecticidal soap to prevent infection. 

How To Prevent

  • Prevention is better than cure. So, keep your cactus in a well-lit area, to help resist any infestations. 
  • Keep the plant away from humidity and areas that are humid like bathrooms and kitchens.
  • Also, keep away from other plants that might harbor any pests. 
  • If any plant displays anything suspicious such as discoloration or pests it’s best to isolate that plant. 
  • Water your plant so that it is not stressed.

#8. Cactus Exposed to Chemicals

A cactus can also turn white due to exposure to harmful chemicals like bleach and ammonia. Your plant might have come into contact with the chemicals via your container or your watering bucket.

What To Do

Here are some measures you can take to help your cactus recover from unintentional chemical exposure.

Place your cactus in the sun for a few days, bringing the plant back indoors at night. This is to allow the plant to photosynthesize and give it a chance to detoxify. Sanitize all utensils used to pot your plants, and clean surrounding areas by washing with hot water and soap. 

After this, continue watering your cactus until you see new growth appear, this is an indication that your cactus has recovered. If after three months there is no new growth, you can well assume that the plant will not recover and that it is dead! 

How To Prevent

  • Make sure any chemicals are sealed properly and kept separately. 
  • If there are any toxic fumes or smells keep them away from your plants. 
  • Keep your plants in a well-ventilated area to avoid contact with gaseous chemicals.

#9. Rotting Cactus

Root rot is another cause for concern. Symptoms include a brown color on the outside and a soft pudding-like feel on the inside. The rotting cactus turns white due to the salt build-up, which in turn makes for an environment that bacteria favor. 

It’s not just salt buildup that induces bacterial infections. Overwatering can induce root rot. So poor air circulation can also create moist environments for bacteria and fungi. 

At times the rotting cactus will have roots that are rotting too, making it impossible for the plant to absorb water. As a result of this, they are exposed to the sun or rain leading to more rotting problems and infections.

What To Do

If rotting is turning your cactus white, cut off the rotting parts with a pair of shears. Reduce watering and take the cactus out of the pot. Repot the plant with a fresh cactus mix that has been treated with a fungicide or an anti-rot formula.

Then place your cactus in a well-ventilated area with good air circulation and that has bright indirect light. Keep an eye on your cactus to see that it does not develop any white spots after being repotted.

But you have no cause to worry! In two weeks your cactus should be on the way to recovery. And if properly treated your cactus should not suffer any lasting damage.

How To Prevent

  • To prevent cacti from rotting, a few rules need to be observed. 
  • Do not overwater your cactus. 
  • Cut off any dead or decaying parts. 
  • And do check your plants now and then.

#10. Fungal Infections in Cactus

Fungal infections such as cactus erythema can be another reason that your cactus is changing color. This condition usually begins with red spots or raised areas with yellow or brown outlines.

The infection usually begins at the base of the plant but can start anywhere.

What To Do

To treat the cactus erythema, trim away the infected parts and treat them with a fungicide. Improve the air circulation for the plant and mist daily.

Place the plant in a sheltered location outside, one that does not receive too much direct sun. It must receive some sun but not enough to scorch the plant.

How To Prevent

  • To prevent cactus erythema good air movement is essential. 
  • Get into a good watering system and be vigilant in checking for disease and pests.


Your cactus turning white could be a result of several reasons. Finding the exact cause fast and addressing it will help your cactus recover. 

Cactus plants can turn white because of cold, sunburn, poor ventilation, overfertilization, overwatering/underwatering, pest infestation, chemical exposure, rotting, or infections (bacterial/fungal). 

How To Prevent Cucumber Leaves From Turning Yellow?


How do you know if your cactus is dying?

Your cactus is dead when it appears dry, discolored, or shriveled up. Also, when all growth ceases for a long time, you will know your cactus is dead. 

Why is my cactus turning light green? 

Cactus plants will commonly turn pale green or even white when they are under stress or strain. Although many situations can cause these effects, a lack of sunlight is the most probable. Get your cactus more sunlight to help reverse this discoloration.