Yellow Upper Leaves on Tomatoes

Question

I planted tomatoes (various varieties) in April, May and June. The first two groups have grown well, but the upper leaves are turning bright yellow at the stems.

Answer 1

Tomato plant leaves turn yellow for many different reasons. Here is an article that you may find helpful: https://www.gardeningknowhow.com/edible/vegetables/tomato/yellow-tomato-leaves.htm