Alocasia, also known as elephant ear or African mask, is a popular houseplant with large, attractive foliage. The leaves have a deep green color with white veins running through them, creating a unique pattern that brings a tropical vibe to any indoor space.
Although not highly susceptible to many diseases, Alocasias are not completely immune to certain problems, and if you notice your plant’s leaves turning brown, you will need to do some investigation to determine the cause and take the appropriate action. Leaf scorch due to direct sunlight exposure is very often the cause, but it might also have to do with long-term neglect or inappropriate growing conditions.
Hopefully, this guide will help you determine why your Alocasia’s leaves are turning brown, as well as what you can do to save your plant.
Why are my Alocasia leaves turning brown?
1. Dehydration due to underwatering
Underwatering an Alocasia will, in time, result in dry, crispy, brown leaves and receding soil. It is extremely important to maintain a regular watering schedule to avoid such excessive dryness.
Alocasia plants come from tropical areas and cannot survive in extremely dry soil. They need to sit in slightly damp soil to keep their foliage healthy and attractive. If you notice your plant’s leaves drooping and losing their structure, The first thing you should do is assess the soil’s moisture levels.
Most growers recommend the finger method to determine the moisture level of the soil. To do this, insert your finger about two inches into the soil near the plant’s stem. If the soil feels dry, it is probably time to water your Alocasia!
An even better way to obtain an accurate moisture content reading is by using a soil moisture meter like the one from XLUX. It is an elegant option if you want to check the soil’s moisture content at root level without getting your hands dirty. This way, you can make an informed decision about when to water your plants.
2. Too much fertilizer
Fertilizing your Alocasia is key to producing and maintaining stunning foliage. However, it can be quite easy to overfertilize your plant, especially if you are a novice gardener. Aside from the leaf tips and edges turning brown, you will also notice defoliation and significant root damage.
Too much fertilizer can make the soil toxic due to the accumulation of residual salts. This buildup around the roots disrupts the absorption of water and nutrients, causing your Alocasia to look sick.
The best approach is to start off slowly when it comes to fertilizing, and monitor how your plant reacts. It is also recommended that you feed your Alocasia only during its growing season, and never during its dormant period.
If you suspect your plant is overfertilized, do not lose heart! Depending on the severity of the damage, you may still be able to save your plant by flushing the soil with water. You can do this once a month to remove the excess salts from the soil.
3. Nutrient deficiency
While too much fertilizer can have detrimental effects on your plant, the lack (or absence) thereof can also lead to undesirable effects.
Alocasias are heavy feeders whose natural habitat is rich in essential nutrients. Unfortunately, growing them indoors will not provide them those nutrients naturally, and this lack of nutrition can cause their leaves to turn brown or yellow. For this reason, it is important to feed your plant with a good-quality fertilizer to ensure proper growth and healthy leaves.
If your plant shows symptoms of nutrient deficiency, you can treat it using a water-soluble fertilizer with a balanced nitrogen-phosphorus-potassium (NPK) ratio of 20-20-20. Begin with a weak solution by diluting the liquid and feeding the plant once a month. As your plant grows, gradually increase the strength and feed it up to twice a month.
As mentioned before, do not fertilize your plant during the cold months, as this is when it is dormant and will not use as much food. Thus, excess fertilizer can build up in the soil and cause root damage. Fertilizer should only be used during spring and summer when Alocasias do the most growing.
4. Exposure to cold drafts
Alocasias are warmth-loving plants and cannot tolerate cold climates or frost. Temperatures below 45 degrees Fahrenheit can be too cold for these tropical plants, causing leaf problems like browning or yellowing.
Remember that prevention is always better than cure, so make sure to protect your plant from cold drafts. During the winter season, keep it away from open doors or windows. If your plant succumbs to the extreme cold, unfortunately the damage can be permanent and you may struggle to bring it back to life.
5. Low humidity
Alocasias thrive in humidity of 50 to 60 percent in their natural habitat. These levels can be tricky to maintain in the average home, and if your plant is not getting the right humidity, it will begin to display symptoms like drooping and browning leaves. The reason for this is that the soil will dry faster if the air is dry. The lack of moisture in the environment also increases plant transpiration and, hence, causes the dry and crisp leaves.
The best way to maintain the appropriate humidity level for these plants is to invest in a humidifier. These devices often come with built-in humidity meters to ensure that your living area has a comfortable climate for you and your houseplants.
6. Temperature stress
Alocasias naturally grow best in temperatures between 65 and 86 degrees Fahrenheit. Temperatures below 50 degrees can make them go dormant, while those above 90 degrees Fahrenheit can burn the foliage, causing the leaves to turn brown and crispy.
Unfortunately, changes in the weather are beyond our control. But there are ways to protect your plant from the stress caused by extreme temperature fluctuations.
First, make sure to keep your plant indoors during the colder seasons. Also avoid watering it in the evening, since the temperature usually drops at night and you do not want the plant to have wet foliage or overly wet soil at this time. Watering in the morning is best; this will also keep the roots hydrated before the oppressive heat of the day starts.
You can also add mulch over the soil – its insulating effect will help protect the plant from varying weather conditions. Every savvy gardener finds mulch a plant-saver!
Lastly, keep your plant away from open areas where it can be exposed to extreme temperatures. Use row covers or shade cloths if you choose to plant your Alocasia outdoors. It is also recommended to keep your plant somewhere with partial shade, so it can enjoy the morning or afternoon sunlight.
7. Lack of sunlight
You will know fairly quickly if your Alocasia is not receiving enough sunlight, because its leaves will turn yellow or brown.
A light-deprived plant will struggle to produce its own energy to grow. Photosynthesis requires sunlight and is an important process for the production of chlorophyll, the green pigment commonly found in plants. Hence, without sufficient sunlight, your Alocasia will not be able to produce or maintain its vibrant, arrow-shaped leaves. It will also develop soft stems that will make it appear droopy and sick.
But do not worry – you can save your plant. As soon as you move it to an area that gets sufficient indirect sunlight, it should return to its normal, healthy appearance!
8. Pest infestation
Pests like mealybugs, aphids, spider mites, and scale insects can cause great damage to your houseplants. These bugs attack the stems and leaves by piercing them and sucking out the sap. This causes brown lesions on the damaged plant tissue.
The easiest way to get rid of this nuisance is to apply an insecticidal soap. Neem oil also works great if you want an organic pesticide. Apply the solution weekly on the affected plant until all the pests are gone. You can also use a mixture of alcohol and water to clean the leaves and remove any crawling bugs you see.
9. Plant diseases
Infectious diseases caused by bacteria, parasites, and fungi can also cause Alocasia leaves to turn brown. These pathogenic organisms can greatly compromise the health of your houseplants – if you do not intervene right away, you may struggle to save your plant!
Depending on the type of disease, some of the symptoms you should watch out for are a droopy appearance, mushy stems and roots, a foul odor coming from the rotting roots, white powdery substance on the leaves, and splotchy or brown spots on the leaves that grow in size as the infection progresses.
If you suspect your plant is struggling with a disease, make sure to isolate it from the rest of your healthy plants immediately. Trim off any dying leaves, stems, or roots. Depending on the cause, apply the appropriate solutions to help save your plant, such as organic fungicides, baking soda diluted in water, or liquid soap.
10. Root rot due to overwatering
Overwatering is one of the leading causes of plant death. Although your Alocasia needs water to stay hydrated, it does not like waterlogged soil. Excess water that pools at the bottom of the pot can decompose the roots and invite pathogenic organisms that will exacerbate the problem.
What does an overwatered Alocasia look like?
Plants affected with root rot will eventually lose their vigor and might show signs like browning leaves, wilting, and slow growth. If this goes on for extended periods, your Alocasia will start losing its leaves and eventually die.
To prevent overwatering, make sure to water your plant only when the top layer of soil is dry. As mentioned before, you can test the soil using your finger or a soil moisture probe. Also make sure your pot has enough drainage holes for excess water to flow out and prevent the soil from becoming waterlogged.
11. Exposure to direct sunlight
The intense heat from the sun is harmful to most plants – exposure to direct sunlight can dry or burn the leaves. Alocasia plants that are exposed to full sunlight for prolonged periods will show scorched, brown leaves and a droopy appearance.
To avoid such exposure, it is best to place your plant near an east- or north-facing window. South-facing windows are usually very bright throughout the day and can harm your plants. You could also use curtains over the window to diffuse the incoming sunlight and make it gentler on the leaves.
Alocasia leaves turning brown is a sign of an underlying issue such as inappropriate watering, incorrect use of fertilizer, too much or too little sunlight, temperature stress, pests, or plant diseases. To revive your plant, it is important to understand the reason behind the browning leaves so that you can apply the appropriate solution. Make sure to give your plant all the care it needs so that you can bring it back to health and enjoy its strong, beautiful leaves for years to come.
Image: istockphoto.com / Ekaterina Petruhan