Succulents are easy to maintain and make for great indoor plants. But that doesn’t mean they don’t have their share of problems. The most common among them are black spots on succulents.
The black spots on succulents are most probably a fungus that has damaged the plant tissue. Another probable cause can be sunburn, causing the leaves to develop spots and pigmentation.
In this article, we will look at what causes black spots on succulents, how to treat them, and prevent further damage to your succulents.
Nine Causes for Black Spots on Succulents
The 9 most common causes of black or brown spots on succulents are given below.
1. Insects and Pests
If the black spots on your succulents are tiny, they may be the result of a pest infestation. Insects like aphids, mealybugs, scale, and grasshoppers attack various plants including succulents. These bites turn into a dark color and may then resemble black spots.
Inspect your succulents closely to see if there are any bugs or insects on your succulents. If you see a white-colored wax-like substance, it may be a mealybug infestation.
Spraying 70% of rubbing alcohol(isopropyl alcohol) can remove most pests from the succulents.
2. Fungus, Rot & Water Warts
Succulents prefer a dry climate for growth. So if you live in a warm and humid area, your succulents may suffer from fungal infection.
Most fungus growth multiplies due to moisture and excess watering. But even if you do not water your plants, moisture in the air can also cause fungal growth.
Fungal growth can cause damage to the plant tissue and finally cause the plant to develop black spots.
Fungus and water warts cause round black spots that grow at an alarming speed. Affected leaves have multiple black spots and fall off when it is completely rotten.
If you suspect a fungal infection, spray a fungicide on your succulents every week.
If you live in a humid area, limit watering your succulents. Also, never spray water on the leaves as this can cause further decay on damaged leaves.
3. Viral Infections
If your succulents have black spots on their underside, they may be black ring virus. Tospovirus, the same virus that causes wilt in tomatoes can also affect succulents and cause black spots.
There is no cure for a viral infection. Cutting off the leaves and disposing of them far away so that you don’t risk spreading the virus to other plants. Also, disinfect all your gardening tools to keep them free from viruses.
4. Sunburn
If the spots on the leaves appear dry, the leaves may be sunburned. Even though sunlight is good for plants as this helps them to make food, too much sun can be a problem.
If your succulent is placed in strong direct sunlight, your succulent may have a difficult time getting used to it. Succulents that have been in shade for a long time and are then exposed to direct sunlight, could end up with burned leaves.
Sunburned succulents can be saved if you stop their exposure to direct sunlight. Though the burned leaves may not heal and change back to normal, you can still stop other leaves from being burnt. Remove the damaged leaves and ensure that you keep your succulents in shade or indirect light.
5. Chemical Burn
If you use a chemical fertilizer that is not recommended for succulents or over-fertilize your plants, they may get burned due to the chemical. Succulents generally don’t need fertilizers for growth. Using coco-peat or compost in limited quantity is the best way to nourish your succulents.
6. Frost
If your succulents are exposed to sub-zero temperatures, they may develop black spots similar to what happens when they are sunburned.
Extreme cold temperatures may damage plant tissues and these dead tissues can lead to dark spots.
If you live in a place where temperatures frequently go below zero, then using a frost cloth to cover your succulents can prevent them from developing black spots.
7. Mineral Deficiencies
If your succulents’ leaves are losing color, withering, and developing black spots then this may be an indication of a mineral deficiency.
Black dots at the base of the plant is a clear sign that there is some mineral deficiency that prevents the succulents from absorbing nutrients through their roots and stems.
8. Overwatering
Overwatering of succulents is one of the most common reasons for black spots to appear on succulents.
Succulents hold excess water in their stems and leaves because they are originally meant to survive in hot and arid regions.
The extra water that the plants may hold due to overwatering causes the leaves to bloat and capillaries to burst. This can cause leakage and will eventually lead to the formation of black spots and rotting of the leaves.
9. Trauma
Trauma caused due to falls or scratches while potting the plants can turn into dark spots later on. These spots are not uniform in shape and are also not uniform in size. Even though this is not due to a health issue with the plant, such spots don’t heal.
All you can do is either remove the leaves if they appear ugly or just wait for them to fall off naturally.
How to Prevent Black Spots on Succulents?
Even though black spots on succulents can appear all of a sudden, you can still take some steps to prevent them from forming.
Below are some steps that you can follow to prevent black spots from forming on your succulents.
Frequent Inspection
Regular check-ups of your succulents will help you detect black spots that have started to appear and figure out the cause.
Eradicating the root cause in time can help save your plant and stop the infestation from spreading.
Quarantine Infected Succulents and Re-Pot Them
If your succulents are infected with a virus, it is advisable to quarantine them and separate them from other plants to prevent the spread of the infection.
If your succulents are infected by pests or a fungus, separating them and treating the infection gives you a chance to save your plant and at the same time also keep your other plants safe.
Once the infected is cleared, you can then re-pot your plant. This gives you a chance to further inspect the base of the plant’s root for any other infection or pests.
Also, as a general precaution, always keep new plants that you bring away from your other plants. This ensures that the new plant doesn’t pass any infection that it may have to others or does not get infected from anything that your existing plants may have.
Keeping the plants quarantined also gives a chance for any existing pests or insects on it to hatch and become visible so that they can be effectively eradicated.
Ensure Hygiene In Your Garden
Keeping your garden hygienically clean is important for your plant’s health. If you are keeping the succulents indoors, ensure that the place is dry and clean.
Do not leave dead plant material lying in your garden. This can become a breeding ground for fungus and other insects. If you are collecting plant material for making compost, ensure that you collect them somewhere away from your garden and that it is thoroughly dried.
Ensure Your Pots Have Drainage Holes
Overwatering is one of the most common damage-causing factors in succulents. So ensure that the pots you use have sufficient drainage holes and are not blocked. This will help excess water to drain out and also prevent root rot in the future.
Lookout For Bugs
Bugs and pests are your succulents’ worst enemy. Inspect your plants for any sign of infestation. Regular spraying of neem oil or Isopropyl alcohol will ensure that bugs and insects do not make your plants their nesting grounds.
Make Sure Succulents Receive Enough Sunlight
Even though succulents can grow well indoors, but they should be provided adequate sunlight once in a while. An easy way to do that is to keep your succulents and indoor plants out once a week. But do not keep them out for too long or they may get sunburnt.
Keeping your plants on a window sill that receives some sunlight during the day is good enough. Sunlight exposure regulates the water in your plants and keeps them well maintained.
Succulents that lack adequate exposure to sunlight tend to grow thinner as they try to grow up seeking sunlight.
Maintain Proper Temperatures
Ensure that your succulents are not exposed to extreme temperatures. The ideal temperature for them should be between 60 and 70 degrees Fahrenheit.
Extreme temperatures may either cause your succulents to get sunburnt or get damage due to frost.
Keep Humidity Low
Succulents are found in arid and dry regions. Humid regions are not their natural growing grounds. If your succulents develop black spots, it may be due to excess moisture in the air. Keeping the humidity around them will help.
Can Black Spots Spread to Other Plants?
If the black spots are caused due to a fungal or viral infection, they can definitely spread to other plants. On the first sign of black spots, quarantine your succulents and investigate the cause of the black spots.
If the spots are caused due to pests, the same pests can infest other plants as well.
Are Brown or Black Spots on Cactus Needles a Common Cause of Cactus Needle Turning Brown?
Cactus needle discoloration explained: Brown or black spots on cactus needles can be a common cause of cactus needle turning brown. These spots often indicate a fungal or bacterial infection, sunburn, or physical damage. It is important to address the underlying issue promptly to prevent further discoloration and damage to the cactus.
Black Spots on Succulents – Conclusion
Black spots on succulents could be due to a variety of reasons. Some of these can be addressed by quick action. While treating damaged plants may not be possible in all cases, prevention can definitely be done.
Knowing the root cause of the spots can help reduce and eliminate the cause ensuring that your plants stay safe and grow without a problem.
Frequently Asked Questions
What Causes Brown or Black Spots on Succulents, and How Can I Prevent Them?
Brown or black spots on succulents can be caused by various factors. One common cause is overwatering, which leads to root rot and subsequent leaf discoloration.
Another possibility is sunburn, especially if the succulent is suddenly exposed to intense sunlight without prior acclimation.
Fungal or bacterial infections can also result in spots. To prevent these issues, ensure proper watering by allowing the soil to dry out completely between waterings. Gradually introduce succulents to direct sunlight to avoid sunburn.
Additionally, maintain good airflow around the plants and avoid overcrowding to prevent the spread of infections.
Can I Save a Succulent with Brown or Black Spots, or Should I Remove the Affected Leaves?
In many cases, it is possible to save a succulent with brown or black spots. If the spots are due to overwatering, stop watering the plant immediately and let the soil dry out completely.
Remove any affected leaves using clean, sharp scissors or pruning shears. Make clean cuts close to the base of the leaf without damaging the healthy tissue. Allow the plant to recover in a well-ventilated area with indirect light.
However, if the spots are caused by a severe infection that has spread extensively, it may be best to remove the entire affected plant to prevent the infection from spreading to others.
Are There Any Natural Remedies or Treatments to Combat Brown or Black Spots on Succulents?
Yes, there are a few natural remedies and treatments that can help combat brown or black spots on succulents.
One common method is to apply a diluted hydrogen peroxide solution to the affected areas using a cotton swab or spray bottle. Hydrogen peroxide acts as an antifungal and antibacterial agent.
Another approach is to use a natural fungicide such as neem oil, which can be applied to the affected areas according to the product instructions.
Additionally, improving the overall health of the succulent through proper watering, adequate sunlight, and well-draining soil can help strengthen its natural defenses against infections and promote healing.