A neighbor has mature black walnut trees not far from where I set up my vegetable patch. Another neighbor told me that she was unable to grow vegetables because of the proximity of the black walnuts. This is my third year of gardening. The dark, green leafys have done well in the space, while others have met with mixed success. The biggest failures have been the tomatoes. Plenty of sun, and the tomatoes come along nicely through July, but they seem to get stunted and shrivelled before the big red payoff. Sun is not the issue. Is it the black walnut trees that are to blame?