Switchgrass soil temp and germination

I planted about 3 acres of switch last year and it ended up getting knee to wait high but there were some weeds mixed in. I am up right now and there is alot of green growing, but I do not think the soil temps are warm enough for it to be switch. I know I was told it needs to be consistently 57 degree or higher for about 5-7 days before it actually will be out of the ground. The soil temp for up here (according to MSU website) has it hanging around the low 50s. There was a stint were it was 57, 56, 60 in early May, but everything other than that has been low 50s. I am using the Atlanta location. Our place is about 10 miles northwest of Atlanta. My question is, do you think the switch has come out of the ground yet? I really want to hit the field with gly to kill the weeds that are already growing, but I am nervous switch may already be germinating. I did this last year with a 1 acres patch of switch, and it was amazing the result. The switch took off to 7-8 feet with no weeds whatsoever. It was just good timing to spray. I would love to do the same for this, but a little worried about the risk. I would appreciate any insight on this.
Thanks for the replies!

Switchgrass soil temp and germination