How long do you pre-soak them?
I’ve seen seed packages that say *DO NOT PRESOAK*.
I do it with my snow peas since I get that crop in so early. It really makes a big difference with them.
I don’t know the exact timeline - it probably depends upon how warm it is in your house in general or where you’re sprouting the beans.
A sunny window would be warmer than not, but then windows are a lot more energy-efficient than they used to be. Remember when refrigerators always had a ‘warm’ top to them? I miss those days, LOL! GREAT germination rates on ANYTHING I had on the top of the fridge. No heating mats needed! ;)
I can’t imagine it would take more than a week for green beans to sprout. Mung Beans sprout that fast when I make sprouts for salads and sandwiches, though they are a smaller bean.
The ‘do not soak’ may be for beans that have been treated with an inoculant.