Spots on Orchid Cactus Leaves

Light Exposure

• Brown spots on the leaves of your orchid cactus may be a sign of over-exposure to light. While orchid cacti like the dappling early morning sun or partial sunlight, direct sunlight will cause their leaves to become sunburned, spotted with brown-tipped margins and possibly wilted. Move the cactus to an area with less direct sun exposure to remedy the spotting, and turn off lights at night to avoid overexposure to artificial light.

Temperature

• The Missouri Botanical Garden website warns that orchid cacti may form brown-margined leaves if the temperature levels are not adequate. Orchid cacti prefer temperatures in the range of 40 to 90 degrees Fahrenheit during the summer, but they cannot be exposed to a temperature lower than frost-level, or 32 degrees F.

Over-Watering

• One of the most common problems for cacti is over-watering, which in orchid cacti will present as dark brown leaf spotting. Before watering, check that only the top one-third of the soil is dry to prevent over-watering.

Fungal Diseases

• If your orchid cactus has brown leaf spots that merge and grow into other spots on the leaf, this may be a sign of a bacterial or fungal infection. The only way to remedy an infection is to use a fungicide, remove the infected areas and in the future avoid over-watering, which is often the cause.