Home Gardening Guide Why Is My Cactus Turning White? (Possible Causes and Treatments)

Why Is My Cactus Turning White? (Possible Causes and Treatments)

by gardeningit
Why Is My Cactus Turning White

Cacti are succulents that are native to North and South America. The Cacti species grown as houseplants are relatively smaller than those growing in deserts. These houseplant cacti still come in various shapes and sizes. Some of them also bloom in spring and produce colorful flowers. Cacti are hard to kill plants due to their resilient nature, but it does not mean you leave your houseplant cactus to grow on its own. It still needs some maintenance and care. No matter the species, every cactus has a central, green, cylindrical stem that bears numerous sharp spikes. We have often heard from the cactus owners asking: why is my cactus turning white? It is a common thing that occurs in a cactus. You can easily handle this problem if you know the main cause.

We have enlisted the possible reasons why your cactus could be turning white all of a sudden. Let’s give them a read.

Resons Behind Cactus Turning White

If the stem of your cactus is changing its color and turning pale and white, there is a chance you are doing something wrong with its care routine. Cacti can turn white due to intense sunlight or too little light exposure, freezing temperature, root rot, or a pest infestation. External injuries or excessive pressure on the stem can also lead to a change in the color of its stem.

So, if you have been asking yourself: why is my cactus turning white, you should start examining the above factors for your cactus as one of these could be a culprit.

Give these factors a detailed read and learn how to fix each of the causes.

1 – Cactus Turning White Due to Sunburn

Cacti love the sun and bright light exposure, but these can also get sunburnt. When a cactus is placed in a sunny spot and is not rotated periodically, the side facing the sun can get burnt. The sunburnt side turns white or light yellow. It also happens to indoor cacti that are placed in south-facing window sills. Sunburn on cactus happens mostly in summers when the light intensity and temperature are at their peak.

It is why you should provide shade to your cactus during midday to prevent it from getting sunburnt. Also, do not water the leaves directly, increasing the risk of getting sunburnt.

How to Treat a Sunburn

A sunburnt cactus can recover by itself, but it takes time and attention. It would be best if you moved it to a shady spot or away from a window. It would help if you also watered it more than often to not get dehydrated.

2 – Cactus Turning White Due to Cold Burn

If your cactus has softened and white tissue after a frost, it means it got cold burnt. Cacti can tolerate low temperatures, but frost and snow damage its foliage.

The severity of the chilly injuries depends on how long your cactus was placed by you outside in frost.

It is why you should never leave your cactus outside during extreme winters. The ideal temperature range for its healthy growth is 15°C to 20°C.

How to Care for a Cold-burnt Cactus?

A cold-burnt cactus will heal itself if you place it in a warmer place. It would be best to move it to a greenhouse to grow in the warmth and become healthy again.

If the foliage of your cactus is turning black from white, it means the damage is severe. You should prune the affected parts in the coming spring.

3 – Due to Pest Infestation

Pests are a nightmare for plant owners. It damages the foliage in so many ways that plants can die in days. Pests can be the likely answer to your question: why is my cactus turning white?

So if your cactus is turning white, look for the signs of any pests or insects.

  • If your cactus has white, fuzzy stuff on its stem and spikes, it has mealybugs.
  • Tiny, white, sugary droplets on your cactus indicate it has scales on it.
  • If small web-like structures are spreading between the spikes and on the stem, it means some spider mites have infected your cactus.

How to Get Rid of Pests?

These pests are easy to remove with a cotton swab dipped in rubbing alcohol. Just wipe the stem and spikes with this cotton swab; it will keep all these sap-sucking pests away. If the pests are larger, spray the stem with diluted neem oil or insecticidal soap solution.

4 – Turning White Due to Root Rot

When the cactus is overwatered or planted in poorly draining soil, its stem changes its color from green and white. Cactus turning white on top of the stem due to root rot is not the first sign; it is the roots that first turn white and mushy. So if you notice your cactus turning white and no other causes seem to be the problem, you must take a look at its roots. If the roots are mushy and white, it means your plant has root rot.

How to Save My Cactus From Root Rot?

If your cactus has root rot, you should remove it from its pot and cut all the infected roots. Wash the roots gently, and then plant your cactus in a new pot. You can also propagate your plant in such a situation to produce a healthy new cactus.

5 – Cactus Turning White Due to Insufficient Sunlight

Like other plants, cacti need bright sunlight to grow. If placed in low light conditions, their stems lose their green color and turn paler with the passing days. So if you are wondering why is my cactus turning white, try moving your plant to a brighter spot.

Where to Place My Cactus in a Home?

It would be best if you placed your cactus near a south-facing window. A south-facing window receives bright sunlight for 6 to 8 hours every day, ideal for cactus. However, please do not place your cactus right into the windowsill as it can get sunburnt.

6 – Turning White Due to Pressure Injury

If something hard puts pressure on your cactus, its tissues can undergo necrosis and die. These areas then turn white. These pressure injuries also occur when a cactus is left outside during a hailstorm.

Can a Cactus Recover From a Pressure Injury?

If your cactus has turned white due to pressure injuries, you should remove all the dead parts. This plant will heal by itself, but it will take some weeks to do so.

Basic Care of a Cactus Plant

Apart from treating the root cause of your cactus turning white, you should fulfill all the basic requirements of this plant to keep it healthy and thriving. Here is a quick care guide for your help.

  1. Keep your cactus in bright, indirect sunlight.
  2. Water it every 10 to 14 days.
  3. Plant it in a loose, well-draining potting mix.
  4. Fertilize it at least once a year.
  5. Please place it in a warmer space with 40% to 60% humidity.
  6. Re-pot your cactus every two to three years.

Final Thoughts

Cacti are the easiest plants to grow with ultra-low maintenance foliage. These adorable plants adorn the interior space perfectly with their striking appearance.

However, there is a little tiny problem. Sometimes, the cacti growers complain: why is my cactus turning white? Their cactus is placed in the wrong spot that receives either too much sun or too little of it. It can also occur due to temperature drop, root rot, pressure injury, or a pest infestation.

Now that you know the solution to each of the above problems, you can turn your white cactus back to its lush green color.

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