Plants get the majority of their nutrients from the soil by root absorption.  However 

there are many instances where foliar nutrient supply is both necessary and beneficial:

  • To minimise environmental impact. The usage efficiency of foliar applied nutrients is higher than soil applied nutrients. This can be important in environmentally sensitive areas and areas prone to leaching.

  • To prevent or cure transient nutrient deficiency when nutrient demand exceeds root uptake rate. This may be due to poor root development or rapid crop growth.

  • To by-pass soil conditions which limit nutrient availability and to thereby accelerate plant response. These conditions include adverse soil pH, moisture, texture and aeration.

  • To target nutrients directly rather than rely on indirect transportation through the soil and roots. Examples of this are in preventing nutrient deficiencies of specific organs, e.g. fruit.

  • To supply nutrients to plants with deep root systems, when soil surface application of fertilisers such as P, K, Ca, Mg and trace elements is not effective.