Using Copper Pennies to Help Prevent Blight on Tomato Plants?
If you do see some blight started on one of your plants, it’s time to take action. Remove the leaf and destroy it. Don’t compost the leaf, or just leave it lay, as blight spreads quickly and can kill your entire garden. Once you remove the blighted leaf, cut a little slit in the branch you just removed. Using a knife, cut about 1/2 way through the branch. Insert the penny. The copper from the penny will produce a continuous feed of copper to the plant and will stop the blight from spreading further.
It’s very important that you use a penny made in 1982 or BEFORE. Why? Because these older pennies were made of 95% copper.
If you need a little further instruction, we found this video that may be helpful.