Sierrablen Plus features Poly-S coated fertiliser granules which rely on a dual coated urea granule to regulate the release of nutrients. By using a combination of primary sulphur coating followed by an exclusive outer polymer coating, the release of nutrients takes place according to soil temperature and moisture surrounding the granule.

Large changes in soil temperature and/or moisture do not result in severe fluctuations in the release pattern, ensuring that Poly-S provides a non-surge growth characteristic accompanied by deep greening. To enable a quick response in the Spring or Autumn, most products contain some readily available nutrients.

In common with the Sierrablen range, the length of release is determined by the thickness of the coating allowing good longevity to be obtained from a fine granule controlled release fertiliser.