Regardless of when you plant soybeans flowering still begins just after V3. The difference is the amount of foliage produced from VE to V3 with more foliage produced the earlier you plant.
Soybeans in Illinois can be planted over a 2- to 3-month period, from early April for full-season beans to early July for double-cropped bean. With soybeans being daylength sensitive, how will such a wide planting window and daylength...