Harvest soybeans the moment you see the bottom leaves start to turn yellow but the rest of the plant is green. The entire plant will turn rapidly so don't waste any time because the beans will be too tough to eat.

Pull off all the pods and immediately freeze or cook by immersing in boiling water for five minutes (same for frozen beans). Strain and sprinkle salt on the pods. Then suck the beans out of the pod. They go great with beer or other cool beverage of your choice.

I am first time veggie gardener, so I had this same question and found the same answer about the yellowing leaves. Just to be sure, I picked two beans and boiled them in salt water for 10 minutes to check. They were great, so I harvested them all.

No need to boil them for 10 minutes. 10 minutes is too long... you cook away nutrients. it's already fresh from the garden, you want to maintain the integrity of the freshness of any garden grown vegetable whenever possible.

I find steaming them for 4-5 minutes works well.

Why do soybeans need to be boiled or steamed? For several years I've grown a few rows of soybeans and have eaten the beans raw. Nice nutty flavor.

Tim

TimSt, I got this from Wiki
'For human consumption, soybeans must be cooked with 'wet' heat to destroy the trypsin inhibitors (serine protease inhibitors). Raw soybeans, including the immature green form, are toxic to all monogastric animals.'

http://en.wikipedia.org/wiki/Soybean