Bush bean seedlings have totally stopped growing.

About a month ago or a bit more, I planted some beans. They all came out nicely and grew pretty good, but after their first set of leaves (they are about 6 cm wide) they have almost totally stopped growing. The seedlings haven't grown at all for like 2-3 weeks.
There are no bugs, holes, spots, or anything. The plants seem pretty firm and solidly in the soil (root wise). The plant is upright, not wilting at all, the only thing is it seems pretty yellow to me. Other than that it looks healthy. The soil is freshly bought. Not the best stuff but everything else grows in it fine it seems.



What could be the cause for a plant to totally stop growing? Thank you very much!

Not knowing your location, I'll throw out a few ideas.
.... Temperature too cool or too hot?
.... Soil too wet or too dry?
.... Too shady a location?
.... Soil pH too high or too low?
.... Soil lacking in balanced nutrients?