How Late Can I Plant Timothy or Orchard Grass???

Between a bit of top dressing, all the rain we've had and are still having and spraying for weeds, I'm going to have a fairly decent 2nd cutting. I'm considering putting off killing down my fields so I can get as much yield as possible.

How far into late Summer/Fall can I go temperature and prefrost wise and still plant timothy or orchard grass and expect a successful stand of hay for 2016?

Thanks!
Bill

How Late Can I Plant Timothy or Orchard Grass???