Calatheas are stunning houseplants known for their vibrant, patterned foliage. However, if you’ve noticed brown spots appearing on the leaves, it’s a sign that something is wrong. These blemishes can be distressing, Here’s the silver lining: those brown spots are often fixable with a few simple tweaks! In this guide, we’ll explore the 8 most common reasons your Calathea has brown spots on its leaves and how to remedy them quickly.
1. Inconsistent Watering Habits
Why Does This Happen?
Calatheas are sensitive to both overwatering and underwatering. If the soil becomes too dry or too soggy, the plant’s health can deteriorate, leading to brown spots.
How to Fix It:
- Maintain a consistent watering schedule (typically once a week, but adjust depending on climate and season).
- Use a moisture meter or check the soil with your finger—water when the top inch of soil feels dry.
- Avoid letting your plant sit in standing water, as this can lead to root rot.
2. Low Humidity Levels
Why Does This Happen?
Calatheas originate from tropical environments where humidity is high. If your home’s air is too dry, your plant’s leaves may develop brown, crispy edges or spots.
How to Fix It:
- Increase humidity with a humidifier.
- Place your plant on a pebble tray filled with water.
- Group it with other plants to create a microclimate.
- Mist the leaves occasionally (but not excessively to prevent fungal issues).
3. Tap Water Chemicals
Why Does This Happen?
Calatheas are sensitive to the chemicals found in tap water, such as chlorine, fluoride, and heavy metals, which can cause brown spotting.
How to Fix It:
- Use filtered, distilled, or rainwater instead of tap water.
- If using tap water, let it sit overnight to allow chemicals to evaporate before watering your plant.
4. Overfertilization
Why Does This Happen?
Too much fertilizer can cause a build-up of salts in the soil, leading to root damage and brown spots on leaves.
How to Fix It:
- Fertilize only once a month during the growing season (spring and summer).
- Use a diluted, balanced liquid fertilizer.
- Flush the soil with distilled water every few months to remove excess salts.
5. Pests: Spider Mites, Thrips, and Mealybugs
Why Does This Happen?
Common houseplant pests suck the sap from Calathea leaves, leading to brown, speckled spots, yellowing, and curling.
How to Fix It:
- Regularly inspect the leaves (especially the undersides) for pests.
- If you spot pests, wipe the leaves with a damp cloth and insecticidal soap.
- Use neem oil or natural predators like ladybugs to prevent future infestations.
- Keep your plant separate from infested plants to prevent spreading.
6. Leaf Fungal or Bacterial Infections
Why Does This Happen?
Fungal or bacterial infections often occur due to overwatering, poor air circulation, or excessive humidity.
How to Fix It:
- Remove affected leaves immediately.
- Improve air circulation by spacing plants apart.
- Avoid wetting the leaves when watering.
- Use a natural fungicide like cinnamon powder or neem oil.
7. Too Much Direct Sunlight
Why Does This Happen?
Calatheas thrive in indirect, filtered light. Too much direct sunlight can cause leaf scorching, leading to brown spots and fading colors.
How to Fix It:
- Move your plant to a shadier spot with bright, indirect light.
- Use sheer curtains to diffuse harsh sunlight if it’s near a window.
- Rotate your plant occasionally to ensure even light exposure.
8. Temperature Stress
Why Does This Happen?
Calatheas prefer warm, stable temperatures (65-80°F or 18-27°C). Sudden changes in temperature, such as drafts from AC vents or heaters, can cause brown spots.
How to Fix It:
- Keep your plant away from drafty windows, air conditioners, and heating vents.
- Maintain a consistent room temperature.
- Avoid placing your plant near doors that frequently open and close, as this can create temperature fluctuations.
Frequently Asked Questions (FAQ)
1. How often should I water my Calathea?
You should water your Calathea when the top inch of soil feels dry, usually once a week. However, adjust based on the season and humidity levels in your home.
2. Can I mist my Calathea to increase humidity?
Yes, but do so sparingly. Excess misting can promote fungal growth. Using a humidifier or a pebble tray is a more effective method.
3. What is the best type of water for Calatheas?
Filtered, distilled, or rainwater is best. If using tap water, let it sit overnight to remove chlorine and other chemicals.
4. Why are my Calathea’s leaves curling along with brown spots?
This could be due to underwatering, low humidity, or exposure to direct sunlight. Check moisture levels and adjust environmental conditions.
5. How do I get rid of pests on my Calathea?
Use insecticidal soap, neem oil, or natural predators like ladybugs. Regularly inspect your plant to catch infestations early.
6. Can brown spots on Calathea leaves heal?
Unfortunately, once a leaf develops brown spots, it won’t recover. Trim damaged leaves and focus on fixing the underlying issue to prevent further damage.
7. Should I cut off Calathea leaves with brown spots?
Yes, if the damage is extensive. Removing affected leaves encourages healthy growth and prevents potential spread of diseases.
8. What is the ideal temperature for a Calathea?
Keep your Calathea in temperatures between 65-80°F (18-27°C) and avoid sudden temperature fluctuations.