I know trying something differently leads to new discoveries. But I just don`t get it (fall seeding beans in Iowa) most years we`re lucky to finish harvest and any tillage and tiling is gravy, so December planting isn`t even a practical option. What`s likely to happen is a few warm days in March they pop up and get frozen off in late March....or May for that matter.
I don`t mean to be a Debbie Downer, but other than learning some other unrelated seedling vigor discoveries, this isn`t for someone with limited resources, let me put it that way 
A couple decades ago Fielders Choice hybrids had a seed coating that wouldn`t allow germination until the soil temp reached 50°, not something that caught on. One would think, it germinates once or a possible number of times and you get a string of not uncommon 18° nights in later April and that`s all she wrote for that plant. At least if you plant the 15th of April and worse case the seed sits 3 weeks or germinates safely underground until May warmth pulls it out of the ground, you have a fighting chance.
If it would work and it becomes normal to harvest, til ...and plant in the winter, what are we supposed to do in the spring?
https://www.agriculture.com/crops/planting-soybeans-in-december
