black walnut trees
How far from the base of the Black Walnut tree do the fermones effect the fruiting of vegetables, such as tomatoes?
Prince George's County Maryland
Walnut roots can extend in the soil well beyond the crown or drip line of the tree, affecting susceptible plants far from the black walnut. Tree roots can grow as wide as the tree grows high.
Tomatoes are very susceptible to juglone. See the publication from Va Tech for more information. You should consider growing tomatoes in another area or in containers.