I’ve got about 50 acres I plan to plant in winter wheat the middle of Sept next year. Once the wheat dies off in the spring, do sunflowers usually come up without any additional plowing?
I do this to about 60 acres and have for many years. I've tried it 2 different ways. I've left the cows off it for the wheat seed to make for Dove hunting, didn't work. As soon as it headed out the Hogs and Deer ate all the heads off, no seeds. As soon as deer season is over I turn Cows in on it, the cows eat most of the wheat and they disturb the ground enough that sunflowers come up in the Spring.
Bottom line, if you want sunflowers in your wheat field let the cows graze it as soon as deer season is over. If you don't graze it, the wheat chokes out the sunflowers and the ground is not disturbed enough by deer and pigs to get the sunflowers up.
They will come up later than fields turned in January, those fields start coming up in late March. Grazed wheat fields seem to come up more in May, and it depends on late spring and summer rains.