Q.Tomatos Yellow
We are growing tomato plants in a barrel. They have produced tomatoes but all the leaves are turning yellow. Nitrogen has been added as has fertilizer. Watering regularly. What could the problem be? We live in North central Texas, zone 9
Thanks for your help.

Certified GKH Gardening Expert
There are a number of reasons for leaf yellowing in tomatoes. This article should help with pinpointing and correcting the cause of yours: https://www.gardeningknowhow.com/edible/vegetables/tomato/yellow-tomato-leaves.htm