Adjusting Micronutrients

I've ordered a pound each of manganese sulfate, zinc sulfate, and copper sulfate to shift my soil levels slightly. Although not far out of the normal range, I'd like to adjust those into the sweet spot for optimal growth of the lawn and gardens.

The chemicals are kind of festive. Zinc sulfate is white, copper sulfate a blue-green, and manganese sulfate a faint pink.

The iron I've dumped (around 5 pounds per thousand) is already binding and the color is decreasing. It looks like I need to add either iron oxide or ferrous sulfate, depending on which one I determine will do the best job. Given my pH of 7.2, I suspect it'll be the ferrous sulfate.

Given that pure ferrous sulfate is around 30% iron, it doesn't require much--no more than a pound or two per thousand square feet at a time, never to exceed 10 pounds per thousand per year. That must never be applied to a wet lawn, and should be thoroughly watered in immediately after application.