The phrase corn knee high by the 4th of July has been around every since I can remember. I believe that was a standard back in my Grandfather's day. Back then they did not have herbicides so controlling weeds was more difficult. They would till the soil twice and kill two flushes of weeds. Then corn planting time was the 20th of May to Memorial Day. Plus the corn hybrids they had were not nearly as cold tolerant as the hybrids today. Remember, corn is a warm season grass.

This year we had corn that was chest high to almost knee high by the 4th of July. Yes, even the corn planted in early June was about knee high by the 4th of July. In the picture is one of my fields of corn that was not anywhere close to knee high by the 4th of July. However, that is a field of sweet corn that was planted June 26, 2019. Normally Birds-Eye-Foods have me plant my sweet corn around Memorial Day. With the wet spring it got a lot later. In the picture you can see my field corn beside the sweet corn. It was up to my shoulders!