Can I turn my lawn into hay with out farm equipment?

[MrSalvage]

I have 1 1/3 acre of land that is all grass. Can I reseed this grass with something more beneficial by hand? Will the new cover crop take over all the grass?

I wonder about this because i see all the wild flowers in my state in the medium strips and along the side of the road. It's very pretty and they certainly don't kill off the grass before they sow the wild flowers.

So i was wondering if i could do the same with a cover crop...