Brassicas will work, but would be nice to get them in in September. Same goes for the cereal grains like wheat, oats, triticale, etc. Wheat will work better as it is more cold hardy than oats are. Maybe, if the herbicide isn't wrong, you can have him plant a perennial and annual clover mix and add some wheat to it. The clover will pop in the spring and the wheat will add to the draw over the winter.
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