What Does a White Mossy Growth on House Plants Mean?

Powdery Mildew

• Powdery mildew, a fungus, is the most likely suspect for causing white mossy growth on houseplants. The fungus thrives in damp conditions, often covering whole houseplants in its white powder. Avoid over watering and remove infected parts of the plant; if the whole plant is infected, throw it out, sterilize the pot and start over.

Salt Layer

• White mossy growth on top of houseplants' soil is a harmless indicator that your houseplants need more water. This white material is actually just salt buildup in your soil. Water affected houseplants heavily, wait 30 minutes and water again to flush excess salt through the drainage holes.

Mealybugs

• Mealybugs can infest succulent houseplants, sucking the juice from the leaves. Adult females create a white, cotton-like, furry material on the stems and leaves of houseplants for laying their eggs.

  If you find just a few outbreaks of mealybugs' cottony material on your houseplant, dab a washcloth in rubbing alcohol and wipe the bugs and their cotton egg nests away. This treatment will not work if mealybugs cover the whole plant or if they have infested the houseplant's roots, however. If the whole plant is covered in mealybugs' cotton material, consider tossing the plant and starting over.

Watering

• Though watering houseplants is essential to their survival, place your finger into houseplants' soil each time before watering. If the soil is very dry, give houseplants an extra drink; if it is damp, skip watering for a day or so.

Prevention

• Aside from careful watering, white mossy growth and other houseplant ailments can be prevented by only buying healthy plants, aggressively cleaning pots between plantings, only using clean soil and placing houseplants in well-ventilated areas.