Common Houseplant Diseases
Houseplant diseases are primarily caused by overwatering, poor air circulation, and contaminated tools. Fungal, bacterial, and viral pathogens thrive when plants are stressed or growing in overly damp conditions.
Quick Diagnosis
Brown or dark patches with yellow halos suggest bacterial leaf spot. A powdery white coating on leaves indicates powdery mildew. Gray fuzzy growth is a sign of botrytis (gray mold). Soft, mushy stems at the soil line point to stem rot. Dark, foul-smelling roots indicate root rot. Stunted or distorted new growth may signal a viral infection.
Causes
Understanding the root cause is the first step to fixing the problem.
- 1Overwatering creating persistently damp conditions ideal for fungi.
- 2Poor air circulation allowing moisture to linger on foliage.
- 3Using non-sterile tools when pruning, spreading pathogens between plants.
- 4Splashing water on leaves, particularly in cool conditions.
- 5Contaminated soil or pots from previously diseased plants.
- 6Stressed plants with weakened immune defenses.
Treatment Steps
Follow these steps to treat common houseplant diseases in your indoor plants.
- 1
Remove all affected leaves or stems with sterile scissors. Disinfect tools with rubbing alcohol between cuts.
- 2
For fungal issues, apply a copper-based fungicide or neem oil spray.
- 3
For bacterial infections, remove affected tissue and improve air circulation. There are no chemical cures for bacterial diseases in plants.
- 4
For root rot, unpot, trim all mushy roots, treat remaining roots with hydrogen peroxide solution (1 part 3% peroxide to 2 parts water), and repot in fresh, sterile soil.
- 5
Isolate diseased plants to prevent spread.
- 6
Viral infections have no cure. If a plant is confirmed to have a virus, it is best to dispose of it to protect other plants.
Prevention Tips
Keep your plants healthy by following these preventive measures.
- Water at the soil level, not overhead, to keep foliage dry.
- Ensure good air circulation around plants.
- Use sterile tools and pots when pruning and repotting.
- Avoid overcrowding plants.
- Remove dead or decaying plant material promptly.
- Do not reuse soil from diseased plants.