There seems to be a lot of questions coming in recently that we just don’t have exact answers to. While extension specialists accept that ‘I don’t know’ may be the most appropriate answer we still want to eventually provide a better answer. 

I guess one of the benefits that come with age is to know there really is no perfect answer to certain questions. Here are a few I have been getting lately.

“My pasture has a _____ (little, some, a lot) of johnsongrass and we got a light frost. It is tall and kind of dried up, and I really don’t think they will eat a lot of it. We are expecting a harder freeze in a day or two. Do you think it is safe to leave the cows out there?”

I have exaggerated this question some, but not much. I am happy that producers recognize that frosted johnsongrass will produce cyanide (prussic acid) and animals that consume a lot of it can be killed. What makes this question so difficult is that we really don’t know how much of what stage of johnsongrass leaf will cause a fatality. We do know that young and very tender growth is very toxic, but how much of that do they need to eat to be fatal. Another unknown is how fast prussic acid is released when plants are frosted.

So how do I answer this? First, I say that I don’t think anyone can give them a definitive answer. Second, I say it is mainly about the amount of risk they are willing to accept. Usually, I explain that if I was their farm manager, then grazing frosted johnsongrass before it’s all the way dried up is just too much risk.

“I planted some _______ (pick your grass) in mid-September and I have not had a rain on it. Do you think I am ok still?” This one is tough, because I really WANT to be able to tell them that everything will be alright. I have to say that no one knows. In 2019, I was advising a farm that was seeding over 200 acres of orchardgrass, a good bit of it on a prepared seedbed. They had a good seedbed and seeded on time (late August). Then we had a month of very hot and dry conditions before rain came. The orchardgrass did come up, but stayed small all winter. Even though I sure wanted it to survive, an extreme winter would have hurt it pretty bad. Thankfully, the winter was mild and the orchardgrass survived.

My point here is that for seedings made in dry conditions, success is mostly determined by the weather. We will just have to wait and see. I hate giving that answer but that’s the truth. ~ Jimmy Henning Farmers Pride