Why Does My Christmas Cactus Have White Spots? (Causes+Fix)

Christmas cactus is a beautiful flowering cactus that grows beautiful green stems. 

However, the plant sometimes suffers due to inadequate care, and you will find the stems dull and damaged. 

You may find ugly-looking white spots on your plants but cannot understand why. Let us find out the reason.

White spots on Christmas cactus may be due to several reasons, such as hard water used on plants, fungal diseases, pest infestation, and sunburn. To fix white spots, identify the root cause and take necessary steps to fix the issue. Also, provide adequate care to the plant to prevent such problems.

It would help if you found the root cause to find out where you are going wrong. We all know different factors are affecting the growth and health of the plant.

In this article, we will learn the reasons causing white spots on your Christmas cactus. Further, we will learn about the factors to help your plant stay healthy and happy.

What causes white spots in the Christmas cactus?

There are a few reasons there are white spots on your Christmas cactus.

1. Hard water spots
2. Powdery mildew
3. Pest infestation
4. Sunburn

These are the prime causes, but there may be other reasons as well which may cause white spots. 

Firstly, check for the above-given problems and then look for the solutions.

How do I get rid of white spots on my Christmas cactus?

If your Christmas cactus has a white spot, we have to check the root reason for the same. 

Knowing the reason is the first as it will save you from unnecessary confusion. Let us learn the reasons and their solutions in detail.

Hard water spots on Christmas cactus

The white spot on your Christmas cactus leaves may show a white texture due to the water you are using. 

Yes, tap water has chlorine, magnesium, and fluoride; these minerals are left behind when used on plants. They start to build up in the soil and leaves, resulting in white spots.

Fertilizing also leads to salt buildup and will add to the condition, making the plant look dull and white.

What happens is that minerals on the stems restrict the stems from absorbing nutrients and water making them weak. 

The water sitting on the plant also leads to white spots as the salt accumulates and leaves spots.

Stop using tap water for watering your Christmas cactus and use filtered water instead. You can use rainwater also. 

If you do not have access to filtered water, collect water in a container and leave it overnight, the minerals will sit down, and you can use the water for your plants.

You can also get rid of the white spots on your Christmas cactus.

What you need:

• Distilled water
• 1 tsp soap (detergent free)
• Microfiber cloth
• Spray bottle

Firstly spray clean water on the leaves and let them stay for some time to loosen the minerals. 

Prepare a mixture of soap and distilled water and soak a microfiber cloth in it. Wipe the leaves using the cloth slowly and gently.

Now rinse the plant to wash away the soap with plain (mineral-free water). Ensure the soapy water is not going into the soil and let the plant dry out.

Powdery mildew on Christmas cactus

Christmas cactus having white spots may indicate fungal disease such as powdery mildew. 

They grow and thrive in humid conditions and a lack of air circulation. They look like white fuzzy and fluffy spots which grow larger gradually.

As it progresses, the leaves have white spots, will be deformed, turn yellow, and eventually decay. 

They weaken the plant and are a perfect environment for pests to attack your plant. It can kill your plant if left untreated.

Check your plant; if it is affected, immediately isolate it to save other plants from getting infected. 

Stop watering and misting as it will add to the humidity environment in and around the plant. It also spreads the fungus to parts that are still unaffected.

Get rid of the powdery mildew in the following ways:

• Isolate your infected Christmas cactus in a separate area
• Please keep it in a good air circulated area, where the humidity is also low. Placing it near a window is a good option.
• Now remove the affected parts of the plants with sterilized scissors and dispose of them.
• If the infection is severe, then make a mixture by adding 1 tsp baking soda to 1 quarter water. Use a spray bottle to apply to the plant’s parts.

Pest infestation on Christmas cactus

White spots on your Christmas cactus may be a result of pest infestation. Some of the common pests are:

Spider mites

Spider mites are too tiny to see with naked eyes, and you may need a magnifying glass to see them. 

This is why planters usually do not even know their plant is infested.

They spread their webs and lay eggs and multiply rapidly. They hide the undersides of the leaves, and you will see a white tint on the leaves.

To get rid of spider mites:

• Isolate the infested plant and keep it in a well-ventilated area.
• Wash the plant to ensure all parts of the plant are flushed with water.
• Make a solution using 1 tsp neem oil and 1-gallon water, and spray it on the plant. Let it stay on the plant.
• Repeat the process every 4-5 days, and make sure the soil is dry before repeating the process.

Tip: You can use the same solution as a preventive measure for your other plants.

Mealybugs

Mealybugs are small pests growing up to ⅕ inch only. They appear cotton-like on the leaves. They secrete a sticky substance called sooty mold. They hide in a safe place and continue to multiply.

They spread all along the plant, making the plant weak. They absorb all the nutrients and moisture from the plant, leading to problems such as discoloration, leaf drops, yellowing, etc.

You may soon lose your plant if they survive in your Christmas cactus for too long. You need to remove these pests; otherwise, they will prove deadly for your plant.

Start isolating the plant from other plants and wash the plant with water. This will remove a lot of pests sticking to the plant.

You can prune the parts that are infested and if there is still infestation, then use neem oil solution.

You can prepare neem oil solution by mixing 1 tsp neem oil with 1 gallon of water. Use this on the plant and leave it. Repeat the process every few days till the problem persists.

You can also go for chemical pesticides or insecticides, but check the instructions before using them on your plant.

Also read: How To Get Rid Of Bugs In Christmas Cactus?

Sunburn on Christmas cactus

Sunburn is also a reason that results in white spots on the leaves of your Christmas cactus. Christmas cacti prefer ample light to grow, but direct light harms them.

Since the plant is growing indoors, they are used to limited conditions. If you expose them to direct light, it will permanently damage the leaves.

The leaves first show brown spots, which may turn red or white. You cannot expect scorched leaves to grow. Hence you may have to get rid of those parts.

To save your Christmas cactus from such a condition, keep the plant in the right lighting i.e. indirect bright light and away from harsh direct sun.

West, south, or east-facing windows will provide enough light for your plant. You must observe yourself if the plant is getting 5-6 hours of indirect light in a spot or not.

If you keep your Christmas cactus outdoors, then keep it under a shape or on the patio. They should not be exposed to direct sun in any case.

Preventing white spots on Christmas cactus

To prevent your plant and yourself from all the hustle, you must take proper care of your plant.

Let us see what factors need to be in check-in details:

Light

Christmas cactus love light. They grow in the canopy of trees in their native environment. They are not very much exposed to direct light due to growth in the canopy of trees.

Indoors also, they are living in limiting conditions. They need indirect light for as many hours as possible. 5-6 hours of indirect light will serve the light needs of your plant.

Low light is also not recommended as the plant’s growth slows down and attracts fungal diseases, pests, etc. The plants dry out slowly, and the entire functioning of the plant also slows down, which results in slow growth.

Direct sun results in sunburn on the leaves. The leaves and the entire plant suffer from dehydration.

Ensure that the Christmas cactus is receiving enough bright light, which is indirect, either natural or artificial. 

You can also use both ways to fulfill the plant’s light needs. There is no hard and fast rule to it.

Also read: How Much Light Does My Christmas Cactus Need?

Water

Watering right is very important, as improper watering will harm the plant and lead to several problems.

When you overwater your Christmas cactus, the excess water in the soil will suffocate the roots and soil. 

This condition leads to root decay, pest infestation, and fungal diseases, leading to white spots, yellowing, weak plants, discoloration, etc.

Water our Christmas cactus such that they are neither overwatered nor overwatered. The best way to do that is by checking the soil.

Touch the soil to feel the soil moisture. You can also go deep in the soil up to 2 inches and check if the soil is moist or dry from within. 

If the soil feels moist, hold on to watering for the next few days till the soil dries out.  

Check the drainage system of the container. Also, use filtered or rainwater to water the Christmas cactus plant to prevent white spots.

During winters, water the plant only when the soil is completely dry. Being cacti, they can tolerate underwatering a little more than other plants.

Also read: How Often To Water Christmas Cactus?

Fertilizing

Fertilizing your plant is essential for boosting its growth. 

It helps in fulfilling the nutrient needs of the plant. Christmas cacti are light feeders, and over-fertilizing them can take your plant away from you forever.

Overfeeding may boost your plant’s growth initially but later will gradually damage the soil, roots, and entire plant. 

The quality of the roots and soil decrease due to excess salt buildup. It burns the roots, and the nutrient content in the soil also goes down.

It creates a perfect situation for the pests, diseases, and fungi to grow and thrive.

Fertilize your Christmas cactus by diluting a balanced houseplant fertilizer or fertilizer specially formulated for cactus. 

Fertilize only during the growing season and avoid it during winter.

Also read: Do Christmas Cactus Need Fertilizer?

Pruning

Pruning helps stimulate the growth of the plant. It also reduces the weight of the stems on roots and pot. 

If you skip pruning, the weight of the stems will create pressure on the roots. The plant may even fall upside down and may damage the plant physically.

The leaves may turn yellow, brown, and leggy due to a lack of pruning. 

Prune the plant to keep it healthy and stimulate its growth. Always use sterilized scissors while pruning the damaged parts.

Also read: Why Is My Christmas Cactus Leggy? (+How To Make It Bushy)

Repotting

Christmas cactus like to stay root-bound and need to repot in 4-5 years. If you repot them frequently, the plant may become weak and vulnerable. 

It will stress them and may lead to several problems such as browning, drooping, leaf drop, and stunted growth.

Repot your Christmas cactus in 4-5 years; that is important because the soil loses its nutrients, and roots have overgrown the pot. If not reported on time, the plant becomes weak.

Repotting in a fresh, sterilized soil mix in a slightly larger pot allows the roots to grow freely. The pot should have a proper drainage system, and the soil should be nutrient-rich

Also read: How To Care For Christmas Cactus Plant? (Ultimate Care Guide)

Tips for a healthy Christmas cactus

• Keep your Christmas cactus in a brightly lit area, but the light should be indirect.
• Water the plant only when the soil is dry. Touch the soil to feel the moistness.
• Fertilize in the growing season with a balanced houseplant food.
• Prune the stem segments from the top a month after flowering.

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Reference: NC State University, Nebraska Extension in Lancaster County, Researchgate, Texas A&M University, Chicago Botanic Garden.