I’ve heard from some producers that, even after killing their annual ryegrass cover crop successfully in the spring, some new plants will come up in the field later that same year or the following year. Here’s what I’ve learned about that:
1. Annual ryegrass seed has the potential to remain viable (latent) in the ground from 3 – 5 years; 3 years in a no-till field and up to 5 in conventional tillage.
2. Some small percentage of seed may not germinate in the same year it is planted. That latent seed may germinate the following year.
3.. Options for this situation: if you don’t want the annual ryegrass, spray it out with glyphosate. But if the “volunteer” seed is prolific enough, you might get a “free” crop of annual ryegrass for the next cover crop season. Or, you can drill or broadcast more seed on top of it.