Osmocote Plus and Osmocote Classic products are 100% coated and designed for use in greenhouses with herbaceous crops. Controlled release fertilizer applications to landscapes can provide a season-long feeding with a single application and help reduce nutrient runoff as well.
How long does Osmocote Fertilizer really last? Osmocote labels contain information on the expected fertilizer longevity. For example, Osmocote 18-6-12 has listed longevity of 8-9 months at 70 degrees Fahrenheit. This is a reference point based on a constant soil temperature, as measured in a lab.
Is Osmocote safe to use in the greenhouse? Yes, Scotts has several state-of-the-art research greenhouses in Marysville, OH and we have conducted many phyto-safety trials with these products at higher than label rates to prove this.
How much Osmocote fertilizer should I use? The correct fertilizer concentration for a particular operation will depend on a number of factors including feeding frequency, crop type, crop stage, growing media, pot size, leaching fraction and environmental conditions. Osmocote labels have generic suggested application rates to help guide a grower, but the only way to determine an effective and optimal rate for your specific conditions if to conduct a rate trial.
How much Osmocote fertilizer should I use on flowerbeds or in the landscape? Osmocote 14-14-14, 18-6-12 and Osmocote Plus 15-9-12 (8-9 months) are the formulations generally recommended for this purpose. Product can be top-dressed around the drip zone of the plant and either gently scratched into the soil surface or covered with mulch. Recommended rates: apply 10-15 lbs of Osmocote 14-14-14 per 1000 sq. feet of area per application (or 1 to 1.5 teaspoons per sq. ft). For maintenance this application can be repeated every 3-4 months. Since Osmocote 18-6-12 or Osmocote Plus 15-9-12 are longer term products, only 1 application per season is generally required, although there could be a reapplication after 6 months in warmer climates. Recommended rates are 10-20 lbs per 1000 sq. feet of area per application (1-2 teaspoons per sq. ft).