The invention relates to an apparatus for applying foliar spray. The apparatus (1) includes supply means (2) in the form of a water tank (4) with pipe (5) extending from the tank, through a reverse osmosis water filtration unit (12), pump (6), and valve (7). A solute container (8) for holding solute (9) in the form an electrolyte solution of sodium ions (Na+) and bicarbonate ions (HCO3-) formed by mixing sodium bicarbonate and water (3) from the supply means (2) is also included. A combinatory part (10) is connected to an ion exchange part (15) through valve (19), pipe (17) and pump (18). The prepared solution is the product of passing the diluted electrolyte solution (11) through the ion exchange column (15) and may be applied to the foliage of plants (26) through pump (27), pipes (28), and finally micro sprayers (29).