Phytotoxicity is the effect of any compound or chemical on a plant and how it damages the plant. I use baking soda to prevent leaf spot and early blight. A concentration of 2 tablespoons per gallon worked fine when temperatures were under 90 degrees. When it hit 100 degrees this week... the plant leaves burned. Spraying time and outside temperature need to be considered when treating your tomatoes and vegetables. I am using 1 tablespoon per gallon now that the temperatures are over 90 degrees. Please Help Support My Channel: The Rusted Garden - Thanks! Please Visit The Rusted Garden Seed & Garden Shop: https://www.therustedgarden.com/ Here is The Rusted Garden Link to Amazon for Seed Starting & Gardening Supplies http://amzn.to/2FgufvF Thanks for using my link. It helps fund my garden videos! Subscribe to My YouTube Channel (800 Garden Videos) - The Rusted Garden: https://www.youtube.com/user/pilarchik Follow me on Instagram for Harvest Pictures, Updates and Monthly Give-Aways: https://www.instagram.com/therustedgarden/ Visit My Original Blog The Rusted Vegetable Garden: http://www.therustedgarden.blogspot.com Contact Me at [email protected]