|My African Violet plants are developing a orange/rust colored "mold" on the soil and around the edge of the pot. The plants still look healthy, but it will eventually rot off the stem at the level of the soil. What is this? Is there anything I can do for this? Could the soil have been contaminated?|
|There are several possible causes for your plants' problems. These plants are occasionally subject to rots -- root rot, stem rot, and even foliar problems. To reduce the chances of infection, the potting soil for African violets should be either a pasteurized or sterilized mix and it should be quite porous and well draining rather than mucky or soggy. Be sure the plants are propagated from healthy stock. It's also important to provide good air circulation and to keep temperatures warm -- as well as provide good bright yet indirect light. In my experience, the plants need to be repotted about every two years or so: they outgrow their pots and the soil mix deteriorates as well.
I suspect the orange accumulation is actually salts rather than a mold and that the rotting may be caused by overwatering. If you bottom water, avoid leaving the pot in a water-filled saucer once it has "wicked" up enough moisture. (If you water from the top, drain the run-off out of the saucer promptly.) Be sure to use room temperature water. Too, about once a month water thoroughly with plain water from the top to flush out any accumulated salts from the soil. You might also double check your fertilization program -- remember that the plants need less when they grow more slowly in response to reduced light levels or cooler temperatures as we experience in winter. Watering is a bit of an art. Remember that plants in plastic pots dry out more slowly than those in clay pots; large pots more slowly than small, and warmer temperatures accelerate drying. A fresh soil mix will also drain better than an older deteriorated mix.
Good luck with your plants!