Thinning alfalfa orchard stand

I have a thinning alfalfa orchard stand I am hoping to take first cut off in the next few weeks. Thinking about seeding some Timothy grass in after I get the hay off. We are located in central mn and it should be getting nice and warm by that time I'm wondering if it will be to warm to establish Timothy? I am looking to have a higher percentage of grass in my hay anyway.

Thinning alfalfa orchard stand