|I believe I am watering my dieffenbachia correctly. However, one of them seems to get yellow leaves more often than the other. help|
|Yellowing leaves are a generic symptom. There are multiple causes for yellowing leaves which include improper exposure to light, improper watering and even natural dropping of older leaves.
If you have your Dieffenbachias more than 6 feet away from south-facing windows, that may not be quite enough light to keep them thriving. On the other hand, if they are right in front of the window, the direct sun may be too much for them. Keep the light as bright as possible while still protecting them from the sun shining directly on their leaves.
If a Dieffenbachia is in a small pot (6" or less), water it thoroughly whenever the top inch of soil is dry to the touch. For larger plants, allow the two inches of soil to dry out between waterings. How frequently you will need to water will depend upon the amount of light, temperature, pot size, age of plant, root system, and humidity. When in doubt, stick your finger down into the soil to check the amount of moisture before you water your plants. Hope this information helps!