If you are throwing out a diseased indoor plant and are going to put a new plant in the old pot, consider using the microwave before doing so.

A newly potted plant can be contaminated if put in a planter that previously housed a diseased plant. Wash the used pot with hot, soapy water and microwave the dripping wet pot for 1-2 minutes. The microwave kills spores and fungus that might be present. This process works for both ceramic and plastic pots but not metal. To avoid melting, do not heat longer than recommended times. New pots do not need to be washed or microwaved.Overwatering is one of the primary reasons for diseased indoor plants this time of year. Consider these points for care and disease prevention.

- Stems will turn dark and rot when plants have been given too much water. This is called damping off. The roots usually rot first, causing the plant to grow slowly and use very little water. Plants use little water during the winter, anyway, and continued irrigation when it is already moist brings on the root and stem rot.

- Excess soil moisture provides conditions that are favorable for growth of fungi usually present in potting soil. Watering plants only after the surface of the soil has had a chance to dry will usually prevent the fungi from rotting roots and stems. Be sure that pots have drainage holes to allow excess water and salts to leach out. Correct the conditions in the pot rather than masking the problem with fungicide treatments.

- Root rot can be detected by carefully inverting the plant and removing it from the pot to examine the roots. Healthy roots should be creamy white. Diseased roots will be brown or black.

- Sherm Thomson,

USU Extension Service