Osmocote 21-4-8 Slow Release Fertilizer (8-9 Month Release)
Long-Lasting Controlled-Release Plant Fertilizer for Professional & Residential Use
Osmocote 21-4-8 Slow-Release Fertilizer is a professional-grade granular fertilizer formulated to provide steady nutrient availability for up to 8 to 9 months. Designed for use in container gardens, landscape beds, ornamental plants, nursery production, greenhouse growing, and foliage applications, this controlled-release formula helps maintain healthy plant growth while reducing the frequency of fertilizer applications.
The advanced coated granule technology gradually releases nutrients over time as soil temperatures change, allowing plants to receive a more uniform supply of essential nutrients throughout the growing season. This balanced fertilizer blend supports lush green foliage, improved root development, stronger plant vigor, and enhanced overall plant appearance across a wide range of growing conditions.
Product Features & Benefits
| Feature |
Advantage |
| Extended 8-9 Month Feeding |
Provides season-long nutrition with fewer applications |
| Balanced 21-4-8 Formula |
Supports vigorous top growth and healthy plant development |
| Controlled Nutrient Availability |
Helps deliver a more consistent feeding program |
| Includes Essential Micronutrients |
Contains magnesium, sulfur, iron, manganese, and zinc |
| Efficient Nutrient Use |
Helps reduce unnecessary nutrient loss through leaching |
| Professional-Grade Fertilizer |
Suitable for commercial growers, landscapers, and home gardens |
| Versatile Application Methods |
Can be incorporated into soil mixes or applied as a surface treatment |
| Reliable Performance |
Designed for dependable nutrient release under varying environmental conditions |
Guaranteed Analysis
| Plant Nutrient |
Percentage |
| Total Nitrogen (N) |
21% |
| Available Phosphate (P₂O₅) |
4% |
| Soluble Potash (K₂O) |
8% |
| Magnesium (Mg) |
1.1% |
| Sulfur (S) |
8.0% |
| Iron (Fe) |
0.70% |
| Manganese (Mn) |
0.20% |
| Zinc (Zn) |
0.08% |
Recommended Uses
Osmocote 21-4-8 Slow Release Fertilizer is widely used for:
Its extended feeding period makes it especially useful for applications that require long-term nutrient availability and reduced maintenance.
Application Information
| Application Area |
General Use Rate |
| Landscape Beds |
Approximately 9.5–24 lbs. per 1,000 sq. ft. |
| Container Growing |
Adjust rates according to plant size and container volume |
| Potting Media Incorporation |
Blend evenly into growing media before planting |
| Surface Application |
Apply evenly around the root zone and water thoroughly |
Important: Application rates may vary depending on crop type, soil composition, irrigation practices, climate, and desired growth response. Always follow product label instructions for proper application guidance.
Professional Controlled Release Performance
Osmocote 21-4-8 is engineered to provide gradual nutrient release rather than the rapid nutrient availability commonly associated with traditional water-soluble fertilizers. This controlled feeding process helps encourage more uniform plant growth while lowering the risk of nutrient surges and fertilizer stress when applied according to label directions.
Its long-lasting feeding cycle and dependable nutrient delivery make Osmocote 21-4-8 an excellent fertilizer choice for professional growers, greenhouse operations, landscapers, nurseries, and home gardeners seeking reliable plant nutrition with fewer fertilizer applications throughout the season.
