Question
A previously very healthy, 1 3/4" dia, approx 36" tall, three stalk corn plant in a 12" pot is developing brown dried leaf tips and whitish-grey spotting on the leaf edges.  Plant is 3' from western exposure picture window.  Last repotted 18 months ago.
Even the new growth is having same symptoms.

Answer
Hi Jim,

The symptoms you described are indicative of a problem with the roots. Check for roots that are growing out of the drainage holes in the pot. Check also for a mass of roots at the bottom of the rootball. If you find either, they should be cut off and removed; yes, even that whole mass of roots at the bottom. Then add a one inch layer of fresh potting mix to the bottom of the same pot and place the rootball on top of that fresh soil. That won't eliminate the existing leaf spots, but it should perevent future spotting on new growth.

If there are no roots massed at the bottom of the pot, then you are probably letting the soil get too dry in between waterings; not watering thoroughly; or your local tap water is on the hard side. In general, your corn plant should be watered thoroughly (until some water runs through the drainage holes) whenever the top 2 -3 inches of soil feels dry. If your water is hard, switch to filtered, distilled, or rainwater.

Please let me know if any of this is unclear or if you have any additional questions.

Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

You can E-mail me directly at: [email protected]

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