I live in AZ and for years I have had big beautiful grapefruit ready in November. This year they are small and still green. Why would that be?
Certified GKH Gardening Expert
The two most common causes for this condition are: Too much nitrogen fertilization, or not enough phosphorus. Often these problems are one in the same, and other times are not the real issue at all. Sometimes it is actually the pH of the soil that is off kilter.
Here is an article that will explain things in further detail: https://www.gardeningknowhow.com/edible/fruits/citrus/citrus-fruit-thick-rind.htm