Q: You say on your website that aspirin can prevent disease on tomato plants. Where can I find more information about the process?

A: Scientists have known for several years that certain compounds can signal a plant to defend itself against disease before a disease actually arrives. One of these compounds is salicylic acid, a breakdown product of aspirin. Gardeners have experimented with spraying their plants with aspirin water with varying degrees of success. One project with tomatoes found that sprayed plants had more but smaller fruits. You are welcome to be a citizen scientist too. Use 250 mg. of aspirin per gallon of water, maintain an identical control group and report your findings back to me!

Aspirin for Plant Health