I'm not sure just how to grow the pretty ears, but we used to do it often. Make sure yours aren't "clear-coated"! When I was a kid, we'd put a couple of Indian corn kernels in the planter boxes every spring. Then, in the fall when picking & unloading corn into crib, it was always a treat to discover those brilliant-colored ears. It kind of broke up the work of fighting w/wagon endgates & pulling ear corn out into the elevator hopper. There would be some cross-pollination, I believe. You'd occasionally see a normal yellow dent corn w/some colored kernels also.

We don't bother doing Indian corn any longer with thousands of bus/hr going thru combines.