Does magnesium compete with Potassium?
I see several fertilizers that have Potassium and Magnesium at the same time, so I'm wondering if I could safely mix magnesium sulfate with an NPK fertilizer.
Otherwise, would it be better to give them separately to the plant, within a week interval for example?
NPK in not a composition. However fertilizer applications are relatively dilute compared to the mass of soil to which they are applied , so it is difficult to imagine a problem. Generally not a problem for a home owner depending on the exact levels and compositions of the NPK, but the mixed fertilizers can interact. I remember once getting a weak ammonia smell from dry mixed materials before application.
