7 Most Common Reasons Your Monstera Plant Has Brown Spots

By: Joanna
Post date:

If you’ve noticed some unsightly brown spots or crispy edges creeping across those lush, glossy leaves, stay calm…but also grab a stress ball. Those pesky blemishes are likely trying to tell you something’s amiss in your plant parenting ways.

Before you start frantically googling and dreaming up worse-case scenarios, let’s do some real talk.

From moisture maze madness to nutrient negligence, there are several sneaky culprits that can leave your beloved Swiss cheese plant looking a little, well, cheesy.

But have no fear! I’m breaking down the most common browning troublemakers so you can get to the root(s) of the problem.

monstera brown spots

Common Reasons Your Monstera Plant Has Brown Spots

Let’s get straight to the point and uncover why your Monstera has brown spots and how to fix it.

1. Overwatering

Giving your Monstera too much water can lead to root rot, causing brown or black spots on leaves and stems. Root rot occurs when roots sit in waterlogged soil for too long, depriving them of oxygen and promoting fungal growth.

Tips:

  • Check Soil Moisture: Use a moisture meter or your finger to check the soil moisture level. Ensure the top 1-2 inches of soil are dry before watering again.
  • Proper Drainage: Ensure your pot has drainage holes. If not, consider repotting your Monstera into a pot with adequate drainage.
  • Soil Mix: Use a well-draining soil mix. A combination of potting soil, perlite, and orchid bark can improve drainage and prevent water from sitting around the roots.
  • Repotting Monstera with Care: If root rot is suspected, carefully remove the plant from its pot, trim away any affected roots with sterilized scissors, and repot in fresh, well-draining soil. Use a fungicide if necessary to prevent further fungal growth.
  • Avoid Saucers Filled with Water: If you use a saucer under your pot, make sure to empty it after watering to avoid standing water.

2. Underwatering

Not giving your Monstera enough water can damage its cells, leading to brown spots. Consistent moisture is key to preventing this issue.

Tips:

  • Check Soil Moisture: Use a moisture meter or your finger to ensure the soil is consistently moist but not waterlogged.
  • Deep Watering: Water thoroughly until excess water drains from the bottom of the pot. This ensures that all the roots get hydrated.
  • Soil Quality: Use soil that retains moisture but also drains well. A mix of potting soil, perlite, and peat moss can help maintain the right moisture balance.
  • Observe and Adjust: Monitor your plant’s response to watering and adjust your routine as needed, especially during seasonal changes.

3. Tap Water

Chemicals in tap water can build up in the soil, causing root burn and brown, crispy patches on leaves.

Tips:

  • Use Filtered Water: Switch to filtered or distilled water to avoid chlorine and fluoride buildup.
  • Rainwater Collection: Collect rainwater to use for watering your Monstera. It’s naturally free of chemicals and beneficial for the plant.
  • Flush the Soil: Periodically flush the soil with clean, distilled water to remove any chemical buildup.
  • Watering Technique: Allow tap water to sit out overnight before using it. This allows some chemicals to dissipate.
  • Prune Damaged Leaves: Remove any leaves that show significant damage to encourage new growth.

4. Lack of Humidity

Monsteras love high humidity. Low humidity can cause leaf tips to turn brown, eventually leading to larger patches.

Tips:

  • Increase Humidity: Use a humidifier to maintain a humidity level of 60-70% around your Monstera.
  • Pebble Tray: Place a tray filled with pebbles and water under the plant. As the water evaporates, it increases the humidity.
  • Group Plants Together: Grouping plants can create a micro-environment with higher humidity.
  • Misting: Mist the leaves regularly with distilled water, but avoid overdoing it to prevent fungal growth.
  • Place in Humid Areas: Move your Monstera to more humid rooms like bathrooms or kitchens.
  • Monitor and Adjust: Use a hygrometer to monitor humidity levels and adjust as needed.

5. Too Much Direct Sun

Excessive direct sunlight can sunburn your Monstera, causing brown patches.

Tips:

  • Optimal Placement: Move the plant to a spot with bright, indirect light, such as near an east or north-facing window.
  • Sheer Curtains: Use sheer curtains to diffuse direct sunlight if the plant is near a window with strong sun exposure.
  • Rotate the Plant: Rotate your Monstera regularly to ensure even light distribution and prevent one side from getting too much sun.
  • Check Light Levels: Use a light meter to ensure the plant receives appropriate light levels.
  • Prune Sun-Damaged Leaves: Remove any leaves that are significantly sunburned to encourage new growth.

6. Nutrient Deficiencies

A lack of essential nutrients like nitrogen, potassium, or magnesium can cause brown spots.

Tips:

  • Balanced Fertilizer: Feed your Monstera with a balanced, water-soluble fertilizer every 4-6 weeks during the growing season.
  • Specific Supplements: If a specific deficiency is suspected, use targeted supplements like Epsom salts for magnesium or a micronutrient blend for potassium.
  • Soil Testing: Conduct a soil test to determine nutrient levels and deficiencies.
  • Organic Matter: Add organic matter like compost to the soil to improve nutrient content.
  • Avoid Over-Fertilizing: Be cautious not to over-fertilize, as this can cause nutrient burn and worsen the problem.

7. Pest Infestation

Pests such as spider mites, mealybugs, and scale can damage Monstera leaves by feeding on their sap, leading to brown spots.

Tips:

  • Regular Inspection: Check your Monstera regularly for signs of pests, such as webbing, tiny insects, or sticky residue.
  • Isolation: Isolate infested plants to prevent pests from spreading to other plants.
  • Natural Insecticides: Use natural insecticides like neem oil, insecticidal soap, or horticultural oil.
  • Manual Removal: Remove visible pests with a damp cloth or by using a gentle stream of water to wash them off.
  • Beneficial Insects: Introduce beneficial insects like ladybugs or predatory mites that feed on common Monstera pests.

Treatments for Brown Monstera Leaves

Alright, let’s now talk solutions.

Neem Oil for Pests

Overview: Neem oil is a natural insecticide effective against pests like spider mites and thrips.

Tips:

  • Mixing Solution: Combine neem oil with water and a few drops of mild soap.
  • Application: Spray the mixture on affected leaves, ensuring thorough coverage.
  • Repeat Treatment: Apply weekly until pests are eliminated.

Fertilizing Properly

Overview: Proper fertilization ensures your Monstera gets the nutrients it needs without causing harm. Tips:

  • Balanced Fertilizer: Use a balanced, water-soluble fertilizer monthly during the growing season.
  • Avoid Over-Fertilizing: Follow package instructions to prevent nutrient burn and brown spots.
  • Seasonal Adjustments: Reduce fertilization frequency during the plant’s dormant period in fall and winter.

Adjusting Watering Practices

Overview: Monstera plants need a balance between moisture and drainage. Deep but infrequent watering helps maintain healthy roots.

Tips:

  • Watering Schedule: Water every 1-2 weeks, checking the soil’s top inch before watering.
  • Thorough Watering: Ensure the water drains out completely from the pot’s drainage holes.
  • Seasonal Changes: Adjust your watering routine based on seasonal changes and indoor conditions.

Additional Tips to Keep Your Monstera Healthy

  • Consistent Monitoring: Regularly check your Monstera for any changes in leaf color or texture. Early detection of problems can prevent severe damage.
  • Proper Ventilation: Ensure your plant has good airflow to prevent fungal infections.
  • Leaf Cleaning: Wipe leaves with a damp cloth to remove dust and improve photosynthesis.

By understanding these common issues and their solutions, you can keep your Monstera thriving and free from unsightly brown spots. Happy planting!