I have pole beans too, but have little experience with them. Hopefully someone with more experience can help.
I also would be curious as to the problem. Mine are in ground, but always willing to learn more from experienced growers of pole beans. Not some guy who grows bonsai!

Another suggestion i see online is "not enough fertilizer." While I know beans create their own nitrogen, I'm wondering if "not enough fertilizer" can be a problem when growing in containers, because you are constantly flushing out nutrients when watering.

dang...you are getting more questions than answers. My beans are growing slowly...and have yellow/green color to them too. I am getting some good beans with some plants...but I just think something is not perfect here...

Tell us a little about the soil, and if the pot is resting on the ground so there is a soil "bridge" between the soil in the container and the ground - so water has a wicking pathway from the pot into the earth.

Al - (the guy so derisively referred to above who grows bonsai)

I'm not a vegetable expert so my advice might be valueless, but I know for a fact that too much water in the root zone of many plants is one possible reason for yellow leaves. This might not be your issue but too much water can cause this.

One way to check this is to insert a thin wooden dowel into your container and leave it there for a few hours or overnight. Make sure the dowel reaches the bottom of the container. If the dowel is damp when removed then the soil should have enough water. If the dowel is really wet then your soil in the root area might be too wet, and therefore causing yellow leaves.

TYG

guys, I think the posts above are good and probably correct on most counts. I only grow containers...but there are always little nuances that are different....plant to plant. I must force myself to remember that small plants just do NOT need much watering. My large tomatoes need much. One size does not fit all. My little moisture meter works good....and I must trust it!