Confused concerning instructions for taking soil sample for residential lawn. MSU instructions page item 4 states "Take samples to a 3- to 4-inch depth for lawns". Item 4 also states "Each sample should be about 1/2 cup." If I were to use a core sample tool that was 1" in diameter at 4" deep, that sample would only be 5.49 cu inches, about 75% of the 1/2 cup guideline. (A half cup is 7.2 cu inches.)  My home made core tool (13/16" diameter ID) at 4" deep creates a sample that is 2.07 cu inches, about 28% of the 1/2 cup requirement.

Is it better to a) forget the 1/2 cup statement and adhere to the defined sample quantity and the appropriate sample depth, b)  take multiple samples in the same immediate area to  get the 1/2 cup requirement or c) take more than the 10 random sample to come up with a total 5 cups of soil to mix together, returning 1 cup of that final mixture in the soil kit?

Thanks!