• Guaranteed Analysis
Total Nitrogen (N) 21%
Nitrate nitrogen (N-NO3) 5.8%
Ammoniacal nitrogen (N-NH4) 6.6%
Urea nitrogen (Ur-N) 8.6%
Available Phosphate (P205) 4%
Soluble Potash (K20) 8%
Magnesium (Mg) 1.1%
Water soluble 0.6%
Sulfur (S) 8.0%
Iron (Fe) 0.70%
Manganese (Mn) 0.20%
Water soluble 0.13%
Zinc (Zn) 0.080%
Water soluble 0.001%



8-9 Months

Product Code


Osmocote Blend 21-4-8, 8-9M


  • Advantages
  • Recommended Rates
  • Directions
  • Download Product Sheet
  • economical choice for general purpose outdoor production
  • consistent release and accurate longevity across multiple temperature ranges
  • highly efficient nutrient delivery promotes robust growth and maximum economy
  • dual coatings reduce nitrogen leeching and decompose with minimal environmental impact
  • fortified with STEP Hi-Mag micronutrients
  • can be incorporated into growing media or surface-applied in the container
Recommended Rates


  Low Med High
Pounds per cubic yard 6.0 9.5 13.0
Kilograms per cubic meter 3.6 5.6 7.7
Grams per liter 3.6 5.6 7.7



  Low Med High
Pounds per 1000 square feet 9.5 16.5 24.0
Kilograms per 100 square meters 4.6 8.1 11.7
Pounds of nitrogen per 1000 square feet 2.0 3.5 5.0


Recommended rates are intended as a guideline only and may not be suitable for all regions and conditions. It is the responsibility of the grower to determine appropriate rates. Follow label instructions and use care when handling all fertilizer products.

  • verify product analysis, longevity and rate for plants in your production system (for assistance, contact your regional ICL-SF Territory Manager or call ICL-SF Customer Service at 800-492-8255)
  • consult rate tables printed on bag labels and product sheets
  • for incorporation, blend into growing media to ensure uniform distribution of cores
  • do not over-mix (doing so could damage fertilizer coating)
  • growing media should be used within two to four weeks after incorporating fertilizer
  • for top-dress applications, spread fertilizer evenly on container surface (avoid piling fertilizer directly against plant stem)
  • irrigate after application (irrigation frequency and volume should be adjusted during the crop production cycle according to crop type, environmental conditions and desired soluble salt levels)
  • a product trial is recommended before adopting a new fertilizer program or making full-scale changes to standard cultural practices (test several rates on representative plant types)
  • use caution when applying to plants being over-wintered under cover (if you can't monitor soluble salts and/or adjust irrigation practices, avoid Fall and Winter applications
  • store in a clean, cool, dry place
Poly-S coating technology consists of nutrient-packed fertilizer cores with sulfur and polymer coatings regulated by microbial diffusion, not temperature. When activated, nutrition is delivered at a constant, balanced rate regardless of climate or temperature swings.