Need…the mother of invention.

Since the beginning of the cover cropping boom, in the 1990s, innovators have been making continuous improvements to cover crop seeding technology.

Part of the drive to innovate was the need to extend the window of opportunity for the cover crop to survive. Seeding annual ryegrass after harvest didn’t reliably leave enough of a growing season to establish the crop before winter.

Late Summer or Fall Seeding

• Aerial seeding allowed growers to put down cover crop seed while the corn was still in the field. The seed would germinate and establish as the harvest took place, opening up the annual ryegrass to fall sunlight and precipitation.
• Highboy equipment was adapted to do the same thing as planes, and perhaps with a bit more accuracy
• Lately, growers have been mounting air seeders on combines, in those locations where seeding at harvest does leave sufficient time to establish before freezing weather
• This technique takes advantage of doing two things with one pass, saving precious time and money.

Spring Seeding

• The practice of “inter-seeding” began in Quebec and has quickly taken off in the US. The idea, discussed previously on this site, involves seeding cover crops like annual ryegrass after the corn has reached about knee high (v 5 – 7). That gives the grass an opportunity to establish before the shade of the corn puts it into a kind of dormancy for the summer.
• It seems that ongoing research has shown that too much shade can kill the grass. So the innovators are suggesting to plant a shorter variety of corn (less than 7′ tall at maturity) or plant the field at a rate of about 32,000 corn kernels/acre. That will give a bit more sun filtering through for the grass.
• Once the corn is harvested in the late summer, the ryegrass – dormant for the summer – quickly resumes its growth before fall
• This technique has an advantage over fall-planted cover crops simply because it has more time to establish before cold weather.