This is the application of a dilute solution of fertiliser to the leaves of plants, useful as an emergency treatment for correcting nutrient deficiencies or for providing quick supplementary feeding. The absorption of liquid fertiliser is greatest where leaf surfaces are tender, particularly on the under surfaces of leaves or on young leaves that are just expanding. Foliar feeds should not be applied in bright sunlight because the foliage may be scorched.
Applied as a liquid, but direct to the leaves not the compost or soil. Leaves can absorb food direct through the foliage so bypassing the roots; Gives a very quick response; Good way of feeding if the roots are damaged such as newly planted bare root trees/shrubs/evergreens or just as a way of feeding (DOFF make a ready mixed tomato foliar feed – although expensive).