Here's the right way to combat mold on orchids

Here's the right way to combat mold on orchids

Repotting a moldy orchid - this is how it works

Mold on orchids cannot be controlled by simply cutting off the affected aerial roots and sorting out the affected substrate pieces. The pathogens are invisible to the human eye for a long time before they show up as a floury-gray coating. We recommend quarantining the affected plant as soon as the first signs appear and repotting it promptly. You proceed professionally in these steps:

  • Pot the moldy orchid to rinse the substrate with a sharp jet of water
  • Use clean, freshly sharpened scissors or a scalpel to cut off the infected roots
  • Take a new culture pot and fill it with a 1-2 cm high drainage made of expanded clay (€ 17.50 at Amazon *)
  • Pour in a handful of fresh orchid substrate

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Place the potted orchid in the fresh pine bark with a twisting motion. Then fill in more substrate successively, occasionally bumping into the pot on the table for a seamless distribution. Since the mold could form as a result of excessive moisture, do not water or immerse the plant for the first few days. Only daily spraying with lime-free water supplies roots and leaves with the necessary moisture.

Tips for preventing mold

Mold spores feel good wherever continuous moisture dominates. Since orchids nonetheless require a high level of humidity, a good dose of tact is required in this regard. You will deprive mold of its livelihood if you heed the following aspects of care:

  • Spray aerial roots and leaves every 2-3 days
  • Only water an orchid when the substrate has dried well
  • Ideally, immerse the root ball in soft, lukewarm water until no more air bubbles appear
  • Always carefully drain off excess water before putting the culture pot in the planter
  • Water sparingly in winter and spray more often

Simple air humidifiers that are inexpensive in stores ensure the desired humidity of more than 50 percent. In winter, place a bowl filled with water on each active radiator. A splashing indoor fountain or an aquarium in the room are also helpful. Simply fill an existing coaster with expanded clay and water.


If the leaves of an orchid are covered with a floury-gray patina, it is very likely that it is not mold, but the fungal infection powdery mildew. Do not cut off the diseased foliage in the early stages. Instead, you fight the disease with a mix of lime-free water and fresh milk in a ratio of 9: 3. The solution is sprayed onto the upper and lower sides every 2 days until the deposit disappears.