Annual ryegrass seed, as with most other seeds, has a protective device that maximizes its chances for successful germination. But it’s important to know about it, so that you can successfully grow the cover crop and be prepared to deal with any dormancy issues that arise.
Most ryegrass seed, used for cover cropping,is spread in the fall, after corn and soybean harvest. Sometimes, the weather or soil conditions are not ideal for seed germination. So, in some cases, the seed will lie dormant until better growing conditions exist.
But the idea of cover cropping is that you have fields covered year round, so as to prevent water and nutrient runoff. Thus, having your cover crop germinate in the fall is important.
Newer varieties of annual ryegrass have been developed for colder climates in the Midwest. And yet, getting the ryegrass to germinate and establish can be challenging, especially in late harvest years with sparse rainfall.
Those in more northern latitudes of the Corn Belt are now going to interseeding (seeding the cover crop into standing corn in the spring, when corn is not yet knee-high – v 5 or so.) That can be done with high clearance equipment or by plane. This method avoids the perils of late fall seeding, though it does continue to require good seed-to-soil contact and moisture for germinating.
Oregon State University, a trusted research institution for grass seed science, has published a short paper about dormancy. It’s available on our website near the top of the list of Research links, and if you CLICK HERE you will find it easy to read and perhaps helpful.