Answer: There is no magic formula for fertilizing citrus in Florida. Type of citrus, soil fertility and other factors all greatly affect the need for fertilizer.
Without a soil test of go by, I would suggest your aunt apply 1 cup of a 3-1-2 ratio fertilizer (such as 15-5-10) and 1/2 cup of Potassium Magnesium Sulfate (also called Sul-Po-Mag or K-Mag) per inch of trunk diameter every 4-6 weeks from February through July. Once the tree is 5 or 6 years old and depending on growth, she may choose to reduce the rate by 1/2 and the applications to every two months.
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