Why Are My Plant's Leaves Turning Brown?

You bought a beautiful houseplant, set it up near a bright window, and within a week its leaves were turning brown or even falling off. What did you do wrong? To address the issue, you'll need to be able to answer some questions about your plant, its environment, and the care you've given it.

Your plant's leaves may be turning brown due to insufficient light, too much or too little water, pests and diseases, or even factors like the amount of fertilizer in its soil. Most often, brown leaves are caused by improper water and sunlight for the plant's needs. Luckily, you can typically bring green leaves back to your favorite houseplant with a few changes to its care routine.

Know Your Houseplant

Imagine buying a dog without knowing that it needs dog food, plenty of water, exercise, and affection to thrive. With the best intentions, you might neglect one or more of its needs, and you'd see your puppy grow thin, despondent, or sick. Like animals, plants are living things with specific needs.

But just as puppies are different from kittens, so too are cacti different from ficus plants or spider plants. To provide the optimum conditions for your plant, you need to know where your plant comes from and what it needs to survive and thrive.

Before purchasing a plant, research its specific needs and requirements:

• What kind of soil does this plant prefer?
• How much and what kind of sunlight or shade does it need?
• How much water is enough (and how much is too much)?
• What kind of fertilizer does the plant need, and how often do I feed it?
• Is this plant prone to pests or parasites? If so, how do I eliminate the pests and keep the plant safe?
• Does this plant need extra humidity or moisture?

What Causes Brown Leaves

Even with the best care, brown leaves are fairly common on many houseplants. Keep in mind that it might be perfectly natural for the lower leaves on your plant to first turn pale yellow and then turn brown before dropping off. This happens to many kinds of tropical plants as they grow. Over time, the plant will form a bare stem.

However, in some cases, brown leaves are a sign of cultural problems. If too many leaves are falling off, if many leaves are turning brown at once, or if the upper leaves start browning, your plant might be experiencing one or more of the following problems:

• Not enough light: If lower leaves start turning brown or yellow, the plant might not be receiving enough light. If the discoloration is isolated to the side of the plant away from the light source, it's probably receiving too little light.
• Too much heat: This often occurs in conjunction with too little water, but too much heat will cause leaves to curl, become crinkly, and then fall off. If the plant is also wilting, increase water. If the rest of the leaves are healthy, introduce some airflow to cool down the plant.
• Too little water: Underwatered plants will first wilt, and then the leaves will brown and fall off. This most often happens from the bottom up, but it might also start on outer leaves on bushier plants.
• Too much water: Overwatering can push necessary air out of the soil. And it can cause root rot, which ultimately means the roots won't function to take up water and nutritions from the soil. Consequently, the plant's leaves will start to brown and die.
• Too little humidity: If the browning is confined to the leaf tip and the leaf margin is still green, it's possible the plant isn't receiving enough humidity. If it's a tropical plant with a high humidity requirement, increasing misting. Too little humidity might also cause black spots to form on leaves.
• Pests/diseases: Random brown spots on a plant's leaves are often the result of insects or diseases, especially fungal diseases, attacking the plant tissue in that area. If this is just occurring on a small portion of the plant, you’ll often be able to trim off those leaves to prevent the problem from spreading. Otherwise, treat the plant with a fungicide or insecticide.
• Improper fertilization: When salts from fertilizer or from softened water build up in the soil, they can cause browning of a plant’s leaf tips. This is why measuring fertilizer is essential and using distilled water is recommended.

Preventing Brown Leaves on Houseplants

The proper environment and care will go a long way to prevent brown leaves on houseplants. Know how much food and water your individual plants need, rather than treating all of your plants the same. And be consistent in your care, as erratic watering and feeding can trigger leaf browning. 

Furthermore, monitor your plants to make sure their soil is draining properly, and test the soil if you suspect a nutrient imbalance. Prune away dying leaves, so the plant can focus its energy on healthy growth. And move it up a container size if it has become root bound.