Nutrigrow Phos-Mag Flower & Vegetable Fertiliser (8-19-10+5Mg) 20kg. Phos Mag fertiliser is a quality mix of NPK specifically designed to promote growth on trees, hedges and woody perennial plants. While this fertiliser is most often used on trees and shrubs, it can also be used on areas suffering from a deficiency in phosphorus or magnesium.
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