Q: My 6-year-old potted sago palm has been very hardy, but the new leaves and some of the old ones are turning yellow. Is the plant dying? I have never fertilized the plant and take it into the garage in the winter with lighting during the day. What is the best fertilizer for the plant? Do I need to replant this in a larger pot?
A: I think you have a nutrient deficiency and I’m leaning toward nitrogen or iron. Palms and cycads are certainly affected by manganese deficiency but the symptoms of this problem are frizzled leaves, not yellow centers.
The fact that you’ve never fertilized seals my diagnosis. Get the special palm fertilizer that contains micro-nutrients and use it as labeled.