There is a near full proof mix that can be planted august 1-sept 15th in your area and it's called succulent succotash. It's basically what i shot my 15 point buck in 3 years ago.
This mix comprises, winter rye, barley, rape, turnips, winfred brassica and purple top turnips. It tolerates low pH's, shade, low organic matter levels etc etc. The rye will give you late season forage and early season forage for 2016. It will provide weed suppression for 2016. The barley gives off soil exudates. The rape tolerates the lowest of the low's of pH's and give one late season forage. The turnips loosen the soil and provide winter energy. Lastly as many know, if there is only 1 thing i would be allowed to plant in a year, i'd always choose winfred brassica. It is has the kale genetics in it and it stays green down to 5 degrees. I love growing 5' tall winfred with the big paddle leaves and high nutrition package.
This is as full proof as it gets.
Otherwise if one's needing to plant before the end of June there is a spring version of succulent succotash that i fine tuned last year, called spring greens. What that has is spring triticale, winfred brassica, a multigraze brassica, radish and swiss chard. My deer hammered it from late june thru gun season. Shot my 150 class buck near that little dittie. Clipped it twice and kept it rolling all year. All for about $30 an acre.