Agronomy researchers in Pennsylvania and Quebec, Canada, are finding success with planting annual ryegrass and other cover crops early in the late spring, when corn is about knee high (“lay-by time”).
The more traditional time to plant annual ryegrass is either immediately after harvest or just before harvest. In both cases, cover crops are weather dependent…they need enough water to germinate and enough growing time before a killing frost to get established. More farmers are aerial seeding annual ryegrass just before harvest, which give it extra days or weeks to establish. Aerial seeding also frees up farmers during an already busy harvest time.
But few have tried seeding annual ryegrass in the late spring, thinking the shade of the corn would stifle growth and the heat of the summer would suffocate it. But over a three year trial in Quebec, the annual ryegrass established in the spring and, because it is shade tolerant, managed to stay alive throughout the summer. Then, once the corn was harvested, the fall weather gave the annual ryegrass all the daylight it needed to thrive.
In Pennsylvania, researchers are working with a new piece of equipment that will seed the cover crop, while also applying herbicide (for residual annual weeds) and fertilizer for the corn.
With a longer growing season, annual ryegrass will better survive harsh winters, sending down deeper roots.
More testing on this seeding method is necessary to prove its value elsewhere, but the results are promising.