Osmocote 21-4-8 contains resin-coated N-P-K, Poly-S coated Nitrogen, and STEP Hi-Mag micronutrients and is our top selling blend. Poly-S is a polymer-coated, Sulfur-Coated Urea (SCU) and is exclusive to ICL Specialty Fertilizers. It carries significantly more coating than the average SCU on the market. Poly-S releases Nitrogen through fissures in the Sulfur coating and diffusion through the polymer coat.
Target Crops/Special Uses
Osmocote Blend 21-4-8 is popular with outside mum and foliage growers as an inexpensive base product in the media or as a topdress. Poly-S boosts the Nitrogen release in the early part of the release period and the resin-coated N-P-K provides a nice even finish to the plants. The STEP Hi-Mag portion of the blend requires watering in before or at the time of planting to move the minor nutrients into the media.