The leaves on flowering plants, vegetables, or other plants can begin to turn yellow. Determining the cause is the first step in returning your plants to good health. This is a guide about plants leaves turning yellow.
Seeing your photo it looks like the plant needs to be repotted into a larger pot with new soil and especially since it's obvious there is a large and elderly portion of this plant sharing the space of the smaller soil level leaves. It's simply in a very small pot just sitting inside a larger pot. The size of the existing larger pot would be perfect so just get enough new soil that will go up to the line you see inside that pot ... It's most likely root bound and crying for more room now in the small pot and needs new soil that has some fresh nutrients. When you repot be sure to gently spread the existing root in the ball out a bit so the roots can easily spread/grow and breathe. Make sure the new soil is very moist (not flooded) when you first repot. Potted plants should be repotted at least every other year.
We have had a lot of rain recently and now my vegetable garden including my corn is getting light green to yellow. Is there something I should add to the soil?
By MaryS from IN
Yes, check garden center for liquid iron or some other brand for it. You have washed nutrients out of the soil. You see this a lot with container planting.