Well-founded resources in German are, as of now, rare. After sorting through a lot of nonsense, those who understand English will find valuable and useful information on the internet. Here are a few links to start your further research:
Detailed instructions for cultivation on the West Coast of the USA
California’s Soyinfo Center offers countless information about edamame, among other things
This is a useful press report about large-scale edamame production in Arkansas
Publication for the arrival of edamame in Australia. Attention: The cultivation instructions are for subtropical climates!