"mixter" wrote:

i recently moved to a home with a few mature black walnut trees. i know
that tomatoe plants can't survive near them. unfortunately, the literature
i have doesn't say how far away i need to plant in order to get those nice
ripe jersey beefstakes.

does anyone here have a clue?

mixter

Plants of the Nightshade family (Solanaceae) which includes potatoes,
tomatoes, eggplant, sweet peppers and chili peppers appear to be
extremely sensitive to the juglone from black walnut trees.
We have many black walnut trees on our property and, unfortunately,
one very large specimen is located rather close to one corner of our
rear garden. While the edge of the garden is a few feet outside the
drip line of this tree, none of the above plants will survive in that
corner. We learned from bitter experience that they will do quite well
for a month or more after planting but then as their roots go deeper
the plants start to decline and eventually die off completely.
Sweet corn, onions, garlic and parsnips planted in this area appear to
be not affected at all by the walnut.
I have tilled up live roots of this particular tree at a distance
greater than twice the radius of its drip line. Therefore, to be on
the safe side, I would recommend that you plant tomatoes no closer
than a distance equal to at least twice the radius of your tree's drip
line.
Good luck.
Ross,
Ontario, Canada.
New AgCanada Zone 5b
43º19' North
80º16' West