One of the greatest advances in plant nutrition is the development of coated fertilizers. Soluble N.P.K. fertilizers are immediately available to plants, dose rates are very low as excess will prove lethal. Conseqently there is a necessity to continuously apply small amounts of soluble fertilizer. It is possible by coating process to create slow release products, which release fertilizer at a pre-determined rate to suit the crop and growing method. The process involves taking soluble N.P.K. ferilizer, converting to a small sphere known in the fertilizer world as a and coating this sphere with an insoluble resin to form a small capsule, approximately 3-4mm diameter. The coating can be varied both in constitution and thickness to give release periods from a few months to several years. The first slow release coated product was the Osmocote brand. This has been superseded by Chempak Summerlong and Yearlong, a new generation of coated fertilizer, which employs different coatings that are thinner therefore, cheaper, and give a higher N.P.K. value.