An experiment was conducted in a 5 year old citrus orchard, for four years, to study the effect of boron (B) containing spray mixtures (nitrogen, phosphorus, potassium + amino acids) on fruit yield and quality and on the foliage B concentration. The foliar fertilization increased the leaf B concentraction, initially low, to within the adequate range. However, there was no corresponding effect on the fruit yield and juice chemical characteristics. The addition of amino acids, urea and potassium chloride to the foliar fertilizer did not affect the absorption of B by the orange (Citrus sinensis) leaves. A second experiment was carried out in orange orchards of different ages, ranging from 3 to 20 years old, in order to determine the effects of repeated foliar applications of B containing spray on the soil B concentration. The soil B concentration increased with increasing orchard age, indicating that part of the foliar sprayed solution fell on the soil and it was higher in soil samples taken under the citrus canopies than between the rows.