I have had trouble growing tomatoes near a walnut tree. The tomatoes do get 4 or 5 hours of sun daily. I have heard that it can be difficult to grow things near a walnut tree – is that true? Could that be the problem?

It is definitely true that it is difficult to grow certain plants under black walnut trees. All parts of a black walnut tree contain a substance called juglone which affects plants growing beneath and around the tree. Different plants have varying levels of tolerance to being planted by black walnuts. Unfortunately, tomatoes are probably one of the worst plants to plant around this particular tree. Some fruits and vegetables that have more tolerance to black walnut trees include: lima beans, snap beans, beets, sweet corn, onions, parsnips and black raspberries. One option would be to try growing your tomatoes in a large-size container in order to keep them out of the same soil as the roots of the tree. Be sure to get a bush type tomato which will not be as aggressive and overtake the container.