Yes, aspirin has been mentioned many times before, But I've never seen any controlled studies that prove that,just anecdotal comments.

The theory is that it improves the immune system of tomato plants,to which I'd add what immune system.(smile).

I'm in the NE as well,and the question I would ask is whether or not there have been any spores of either Early Blight or Septoria Leaf Spot in his area,if he even knows about that,for sometimes the answer is yes, and sometimes no.

No spores embedded in raindrops or spread by wind, then his results, at least to me,don't prove anything.(smile)

Carolyn

Did he grow any control plants, any unsprayed plants for comparison?

Dave

The control plants are all the other growers around him that have the usual blight that shows this time of the year.
Neither he nor I are saying for sure that the aspirin is what is keeping the blight away, but we both have many years experience and either the blight just "skipped" his farm this year or the aspirin is having an effect.

Aspirin is an acid (acetylsalicylic acid ). It is also a thinner. Some people put a tablet in cut flowers water. I think it might prevent bacterial growth, as most bacteria cannot thrive in acidic environment. So that might the reason why the blight bacterium cannot live in that environment.

But, without a controlled study , I would not depend on it. OTOH, since it has no side effects on the plant you can use it.