Updated: 2025
Fungal Infections in Houseplants: How to Identify, Treat, and Prevent Them
Quick answer: Common fungal infections in houseplants include powdery mildew (white dust on leaves), leaf spot (brown/black spots), and mold or fungus on soil. Fixes include pruning infected parts, improving airflow, adjusting watering, and applying fungicides or DIY sprays. For a personalized treatment plan tailored to your plant and environment, try the AI Plant Doctor Tool.
Common Types of Fungal Infections
- Powdery Mildew: White, dusty coating on leaves; spreads in low airflow and high humidity.
- Leaf Spot: Brown, black, or yellow circular spots on leaves.
- Botrytis (Gray Mold): Gray, fuzzy mold often on damaged or old leaves/flowers.
- Soil Fungus: White fuzzy mold on soil surface, usually from overwatering.
- Root Rot Fungi: Pythium and others—roots blacken and collapse.
Takeaway: Symptoms differ, but all thrive in moist, stagnant conditions.
Treatment Options
- Prune: Remove all infected leaves and dispose (do not compost indoors).
- Improve airflow: Space plants apart, use a small fan if needed.
- Adjust watering: Water soil, not leaves; avoid soggy conditions.
- Apply fungicide: Use neem oil, copper fungicide, or baking soda spray for powdery mildew.
- Repot if needed: For severe soil fungus or root rot, replace soil and clean pot.
Pro tip: Always sterilize scissors and pots before reuse.
DIY Fungus-Fighting Sprays
- Baking Soda Spray: 1 tsp baking soda + 1 quart (1 L) water + a drop of soap. Use for powdery mildew.
- Neem Oil Spray: 1 tsp neem oil + ½ tsp mild soap + 1 quart (1 L) water. Effective against many fungal problems.
- Hydrogen Peroxide Soil Drench: Mix 1 part 3% hydrogen peroxide with 3 parts water. Water soil lightly to kill fungus and improve oxygenation.
Prevention Strategies
- Water in the morning so leaves dry quickly.
- Avoid overhead watering indoors.
- Keep humidity 40–60% but ensure good airflow.
- Remove dead leaves and debris from soil surface.
- Rotate plants regularly for even light and air exposure.
Takeaway: Dry leaves + moving air = fewer fungal outbreaks.
Real-World Example
Case study (2025): A VerdeBotany user found white powder on her jade plant leaves. The AI tool diagnosed powdery mildew and recommended a weekly baking soda spray plus improved airflow. After 4 weeks, the infection cleared and new growth was healthy.
Personalize Your Fungus Control Plan
Not every fungus reacts the same way, and some plants are more sensitive to treatments. Tell our AI tool your symptoms and plant type, and get a step-by-step fungal treatment plan.
Helpful Internal Links
FAQ: Fungal Infections in Houseplants (2025)
Is white fuzz on soil harmful?
Usually not—it’s a harmless saprophytic fungus. But it signals overwatering. Scrape off and adjust watering to prevent root issues.
Can I save a plant with leaf spot?
Yes—remove infected leaves, improve airflow, and apply a safe fungicide. New growth should be spot-free if the problem is under control.
Is neem oil safe for all plants?
Most tolerate it, but test on one leaf first. Some delicate plants (ferns, calathea) may be sensitive.
How fast will fungus clear?
Mild infections may improve in 2–4 weeks. Severe cases may take longer or require repotting.