Sheri from Escondido, Ca writes
According to the manufacturer, Coron 18-3-6 will last for up to 30 days in the soil. The longevity of Coron 18-3-6 will also depend on the rainfall and soil type in your area. The iron will remain in the soil until the plants utilitze it or if it gets washed away. Please let us know if you have any additional questions.
Answer last updated on: 09/08/2014