Question
Dear Will,several of my plants have red-brown spots and don't look well. I am sending photos separately. A week ago all were healthy. The affected plants are on a bright sunporch that stays very humid. Temps dropped sharply last week also. Humidity? Temp? Disease? Help!

Answer
Hi Wint,

Thanks for sending me the photos. The suddenness of the discoloration of your plants is due to the drop in temperature. However, the spots on your fern are spores and they are quite normal and healthy. Many ferns can tolerate cold temps, so that is further evidence that the other plants are suffering from cold damage.

Most indoor plants do just fine in high humidity, but only if the temps are warm - above 60 degrees. Cold moisture on the leaves can become a source for fungal diseases.

The damaged leaves will not recover their green color, so you may as well trim them off. If you get them back inside where it stays warm, future new growth should be fine.

If you are eager to keep some of your plant on the sun porch, then let me know just how cold it gets and what plant species you would like to put out there. Then I will be able to tell you if any of them are suitable.

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

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

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