I planted some corn last year on the 4th and it made some good ears but we also had a pretty cool/wet summer last year. I wouldn't be afraid to do it again.
I bought a 7100 6 row for a grand a few years ago. I basically cut the tool bar in half and made a 15" 5 row no till planter. I basically re-did everything on the planter and it works great.
We planted July 14th last year and grew some of the tallest, thickest corn ever. The corn did not ever fully harden but the deer ate it all and we killed our biggest bucks to date, all out of the same field.
