I have pumpkins, cukes, squash, tomatoes, beans. . . Some in pots, some in the ground. Many different locations around the yard but all in the same dirt. All the leaves starting from the bottom turn yellow. They start out perfectly green then yellow but ok then turn brown and die. Some plants are just yellow leaves but growing healthy fruits. What would cause this?
You may not be watering deep enough. Try watering 1-2 times a week for long periods of time, say at least 20 minutes. This will make sure the water gets down deeper and willnot evaporate quickly. This article will have some other reasons for yellowing leaves: https://www.gardeningknowhow.com/plant-problems/environmental/plant-leaves-turn-yellow.htm