All you need to do is feed your lawn iron sulphate the day after it has been raining, as the moisture will dissolve it.

1-2 mg Fe/kg/day up to a maximum of 15 mg/day Adults (dose expressed in terms of ferrous sulfate):Iron deficiency: 300 mg twice daily up to 300 mg 4 times/day or 250 mg (extended release ...

Here we’ve got an iron nail and some copper sulfate solution. Copper sulfate is a compound that contains the metal copper. We start by filling the beaker with copper sulfate solution about halfway.