It's all going to depend on what variety/group of soybean your planting. Like was stated - in the mid-west many time wheat is harvested in mid summer and soybeans are drilled shortly after and those beans are a specific group/variety to do this. They don't get tall and won't offer much forage, but still provide a grain to be harvested in the fall. IF you plant a soybean group/variety that was intended to be a "full season" bean (thus spring planted) and wait too long, then the plant won't have enough time to mature and produce the grain before the weather changes. Your growing season may be very different than what I see here so you need to reach out to someone in your area to help you out with what you are trying to do. Ag soybeans are a science all their own. I don't even begin to try to understand it all.