Q.My Ficus Elastica Is Having Some Dried Up Spot On The Underside Of Its Leaves, And I’m Not Sure What It Is?
I water it once weekly when the soil is dry and place it beside a north facing window… it receives bright indirect light from 2/3pm till sunset.
Certified GKH Gardening Expert
Unfortunately, this looks to be algal leaf spot. Watering on schedule will not be appropriate. These will prefer to remain on the dry side, and down to a depth of about halfway the container.
A moisture meter may be needed to keep track of watering.
Fungicide treatment will be necessary, as well.
Here are some articles that will help: