TwinCitiesPanda
Garden Ornament
As a rule, soybeans do not need very wide spacing for seed saving. I generally use 20-30' between varieties, but can space them as close as 10' apart if they are in different Maturity Groups & have other flowering crops between them. I try to separate group 0 or Group I varieties, with a Group 000 variety between, since they will usually begin flowering at different times. I also try not to grow two varieties of the same seed color, and/or flower color, in adjacent locations... so if a cross occurs, I can catch it quickly. Like common beans, soybean flowers are usually either white or purple - and very small. I've seen bees working the flowers, but with the measures mentioned above, crossing has been uncommon.
Sounds doable then. I have a lot of space, I can certainly accommodate that distancing. I’m already growing Midori Giant Edamame.