Grapefruits with thick skins may have been given too much nitrogen fertilizer. Photo by Ben Kirkby / The Arizona Daily Star
Q: My red grapefruits this year have thick rinds. Is there a way to avoid this in next year’s crop?
A: Thick rinds on citrus may indicate too much nitrogen and a lack of potassium or potash in your fertilizer. Make sure you are using a complete fertilizer that contains some of each of nitrogen, phosphorus and potassium. Since it is the time of year to put down your first fertilizer dose, you can hopefully get this problem fixed before your next crop.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to
