Apply iron(II) sulfate and dolomitic lime at the same time?

Question

I have had good experiences with iron(II) sulfate and dolomitic lime for my lawn. They increase the green colour and prevent moss.

However, I am uncertain whether I should avoid applying these two mineral salts at the same time. I assume that the alkaline conditions provided by the lime promote the oxidation of Fe²⁺ to Fe³⁺ by atmospheric oxygen on the soil surface. I think that Fe³⁺ is less available for plant uptake than Fe²⁺. Furthermore, Fe³⁺ is immobilized in alkaline conditions.

Therefore, I image that I should apply the iron(II) sulfate first and wait until after the next rainfall before applying the lime.

Is my rationale correct, or am I making too much of it?

Answer 1

Apply the iron sulfate first, wait a week to apply dolomite. Wait a week and fertilize! Do this process in the spring and again in the fall.

Answer 2

I don't think it will be an issue. The lime should be put down very lightly if your lawn is already at a good pH level, so it shouldn't really alter the activity of the Fe² much if at all.

If your lawn's pH is low, and you're adding a considerable amount of lime, then perhaps I'd say allowing some time in between applications of the two minerals would be a good call.