If you’re noticing white spots on succulents, it can be a worrying sight. One of the most common causes is a fungal infection, and recognizing the signs early is key to saving your plant. This guide will help you figure out what those white marks mean and exactly what to do about them.
Not all white spots are a death sentence. Sometimes, they’re just mineral deposits from hard water or a bit of sunburn. But often, they signal an unwelcome fungal guest. Telling the difference is your first step. Let’s look at the clues.
White Spots On Succulents – Common Fungal Infection Signs
When fungus is the problem, the white spots have a distinct look. They won’t wipe off easily like dust or water spots. Instead, they might look powdery, fuzzy, or even like small, raised bumps. The spots can spread quickly, especially in humid conditions, and may cause the leaves to turn yellow or brown underneath.
Identifying the Specific Fungus
Two main fungal issues cause white spots. Knowing which one you’re dealing with helps you choose the right treatment.
- Powdery Mildew: This looks exactly like its name. It creates a flat, powdery white coating on leaves, as if someone dusted them with flour. It’s one of the most common fungal infections in succulents kept in stagnant air.
- Mealybugs (Not a fungus, but often confused): These are pests, but they create white, cottony, fuzzy spots that look fungal. They hide in leaf crevices and stems. If the white stuff is fluffy and you see tiny insects, it’s mealybugs.
- White Mold (Sclerotinia): Less common but serious, this appears as a wet, mushy rot with white, fuzzy growth. It usually starts at the soil line or on damaged leaves.
Why Did This Happen to My Plant?
Fungi thrive in specific conditions. If your succulent has a fungal infection, one or more of these factors is likely present.
- Overwatering: This is the number one cause. Soggy soil creates a perfect home for fungus.
- Poor Air Circulation: Stagnant, still air allows fungal spores to settle and grow on leaves.
- High Humidity: Succulents prefer dry air. Bathrooms or kitchens can be too humid for them.
- Lack of Sunlight: A plant in low light dries out slower and is weaker, making it susceptible.
- Contaminated Soil or Tools: Using old potting mix or dirty scissors can introduce spores.
Step-by-Step Treatment Plan
Act fast when you see signs. Isolate the infected plant immediately to prevent spread to your other succulents.
Step 1: Physical Removal and Isolation
Put on some gloves. Carefully remove the most heavily infected leaves. Use a soft cloth dipped in a mix of water and a drop of mild soap to gently wipe off any spots you can. Be sure to throw away these leaves in the trash, not the compost.
Step 2: Apply a Natural Fungicide
For early-stage infections, natural solutions work well. Mix one tablespoon of baking soda with one gallon of water. Add a few drops of mild liquid soap to help it stick. Spray the entire plant thoroughly, making sure to get the undersides of leaves. Do this once a week.
Another excellent option is neem oil. It’s a natural fungicide and pesticide. Mix as directed on the bottle and spray every 7-14 days. Always test on a small area first and apply in the evening to avoid sunburn.
Step 3: Improve the Environment
This is crucial to stop it coming back. Move the plant to a spot with brighter, indirect light. Ensure there’s good airflow around it—a small fan on low nearby can help. Check that its pot has a drainage hole.
Step 4: The Soil Check and Repot
If the infection is severe, you need to repot. Gently remove the plant from its pot. Shake off all the old soil. Inspect the roots and cut away any that are black or mushy. Let the plant and its roots air dry for a day. Then, repot in a completely new pot with fresh, well-draining succulent/cactus mix.
Prevention is Always Better Than Cure
Keeping your succulents healthy from the start is the best defense. Follow these simple practices to avoid fungal issues altogether.
- Water Correctly: Always soak the soil completely, then let it dry out fully before watering again. Never let the plant sit in a saucer of water.
- Use the Right Soil: Regular potting soil holds too much moisture. Always use a gritty, fast-draining mix designed for cacti and succulents.
- Provide Ample Light: Most succulents need several hours of bright, indirect sunlight daily to stay compact and dry.
- Ensure Good Airflow: Don’t crowd your plants. Space them out so air can move freely between their leaves.
- Water at the Base: Avoid getting water on the leaves when you water. Water the soil directly instead.
Common Mistakes to Avoid
Even experienced gardeners can make these errors. Be mindful of them to keep your plants safe.
- Misting Your Succulents: They do not need increased humidity. Misting creates wet leaves, which invites fungus.
- Using a Pot Without a Drainage Hole: This traps water at the bottom, leading to root rot and fungal growth.
- Ignoring Early Signs: A small white spot can become a big problem in days. Address it immediately.
- Overusing Fungicide: More is not better. Follow the treatment schedule to avoid stressing the plant.
FAQ Section
Are white spots on succulents always fungus?
No, not always. They can also be harmless mineral deposits from tap water, physical damage, or sunburn. Fungal spots typically look powdery or fuzzy and spread.
Can I use vinegar to treat fungal infections?
It’s not recommended. Vinegar is acidic and can easily burn the delicate leaves and farina (natural coating) on succulents. Stick to safer options like baking soda or neem oil.
How often should I treat the plant with fungicide?
For natural sprays like baking soda or neem oil, once a week is usually sufficient. For severe cases, you might need a commercial fungicide; always follow its label instructions carefully.
Should I remove all the leaves with white spots?
Remove only the most severely infected leaves initially. For minor spots, try treatment first. Over-pruning can shock the plant. If treatment doesn’t work, you may need to remove more later.
Can the fungus spread to my other houseplants?
Yes, fungal spores can travel through the air or on your hands. This is why isolating the infected plant as soon as you notice the problem is so very important for protecting your collection.
What does powdery mildew look like on succulents?
It appears as flat, white or grayish powdery patches on the leaves and stems. It often starts in small circular spots that gradually merge together. It rubs off somewhat but will return if not treated.
When to Use a Commercial Fungicide
If natural remedies fail after a few weeks, a stronger product may be necessary. Look for fungicides containing sulfur or copper, which are effective against powdery mildew. Myclobutanil is another common active ingredient. Always choose a product labeled for use on succulents or ornamentals, and apply it outdoors or in a well-ventilated area, following the safety directions.
Recovery takes time. After treatment, your succulent may look a bit ragged. Focus on providing perfect care: maximum light, excellent airflow, and careful watering. New growth should come in clean and healthy. If the plant continues to decline, sometimes the kindest thing is to take healthy leaf or stem cuttings to propagate a new plant and discard the mother plant.
Remember, those white spots on succulents are a message. They’re telling you something about the plant’s environment is off. By learning to read the signs—the common fungal infection signs—you can quickly correct course. With the right knowledge and a bit of patience, you can restore your succulent to its former glory and prevent future outbreaks. The key is observing your plants regularly and enjoying the process of learning their needs.