On June 21, the Summer Solstice occurs. The Summer Solstice is the longest day of the year in the northern hemisphere. The days that follow will begin to shorten by about 2 minutes per day.
Significance of the Summer Solstice
The significance for the Summer Solstice is its effect on photo period sensitive plants, such as soybeans. With the onset of the day length decreasing, soybean plants shift growth from vegetative to a reproductive growth phase.
On June 20, I found the first flower on my soybeans at the Agronology 10 Research Center. I normally would advise farmers to have their soybean post spraying completed by Independence Day, July 4. Many soybean post emergence herbicide labels indicate “no spraying after flowering.”