For the past 4 years my dad has had problems with his tomato patch,
a patch that he grows between 14 and 16 plants every year (Zone 5
Chicago). Thanks to the discussions on this newsgroup, it appears his
tomatoes had (and still have this year) blight. The leaves get blotches,
produce one round of tomatoes, and completely whither away and die. Over
the years he still got a huge load of tomatoes and ironically last year
was a record haul however he didn't like how the plants looked after they
produced their fruit and he wasn't getting any secondary or continuous
growth after the first round. So I convinced him to not compost any of
the dead plants this year and move the tomato plot somewhere else next
year.

I'm wondering, after 4 some years of blight, how many years will it take
before he can grow tomatoes there again? Next year the plan is to grow
wildflowers in the plot and I plan to do a fall planting of seeds for
him. My dad likes to grow herbs and other veggies and I'm wondering if
that would be OK to do there while the plot heals or should we just stick
to the wildflowers?