⚠ ModeratePothos Brown Spots — Bacterial Leaf Spot & Cold Water Damage
Commonly affects: Epipremnum aureum — all cultivars
Irregular brown spots appear on the leaf surface, sometimes with a yellow halo, sometimes water-soaked at the edges before turning brown. Spots may enlarge over days and merge. Bacterial leaf spot (Pseudomonas or Erwinia spp.) is a common cause in humid conditions with poor air circulation, while cold water applied directly to warm leaves causes cell damage that manifests as brown irregular marks. These two causes are sometimes confused — bacterial spots have a yellow halo and may spread; cold water damage is more random in placement and static.
Potential Causes
- 1Bacterial leaf spot (Pseudomonas spp.) — enters through natural openings or wounds; spreads via water splash
- 2Cold tap water applied directly to leaves, causing rapid cell contraction and death at points of contact
- 3Physical damage from cold draughts, windowpane contact in winter, or freezing temperatures below 10°C
- 4Fungal leaf spot in conditions of persistently high humidity with poor air movement
Solution Steps
- 1Identify the cause: if spots have yellow halos and are multiplying — bacterial. If spots are random, irregular, and stable — cold damage.
- 2For bacterial spot: remove affected leaves, improve air circulation, and reduce overhead watering. Apply copper-based bactericide as a preventive spray.
- 3For cold damage: move plant away from cold windows and draughts. Ensure water used for irrigation is at room temperature before application.
- 4Always water at the soil level rather than overhead to prevent wetting foliage.
- 5Isolate the plant if bacterial infection is suspected to prevent spread to neighbouring plants.
Prevention Tip
Use room-temperature water for irrigation and avoid wetting foliage — direct substrate watering prevents the majority of both cold water damage and bacterial leaf spot in Pothos.
