I have several grapefruit trees in my garden about five years old. Till two years back they were giving fully ripped grapefruit. However for past two years the fruit grows to its normal size but is all dried inside without juice. It's looks just normal but without any weight. Can someone please advise for the probable causes and remedies if any?
This ,typically, happens when there is too much nitrogen present in the soil, or too little phosphorus. Adding more phosphorus will help the plant take less nitrogen up. Recursively, too much nitrogen affects the uptake of phosphorus. Here is an article that will explain in more detail: