I put some epsom salts on my tomatoes last week and we seemed to have an overnight positive response. The leaves are much greener and the plants look stronger. The green tomatoes are bigger. It did rain overnight so the growth and tomato size might be from that but the greener plant I think is from the epsom salts.
I didn't have a sprayer so mixed two TBSP of salts into two gallons of water and saturated the roots of three plants with that mixture. I also sprinkled some over the tops of the plants.
If three plants got two TBSP that means each plant got saturated and sprinkled with two tsp of salts in water.
Great idea and I'm glad I did it. Foliar spray is probably a better idea but I also saw mention of the root saturation method and that worked for me.