Homemade sprays when mixed or used incorrectly or as some sort of preventative when a problem doesn't even exist yet usually do more harm than good. And that is if they even work when there IS a problem. That is the case here. Baking soda and dish soap solution are 2 separate solutions used for different problems and have to be very carefully mixed in exactly the right proportions to avoid plant damage. You don't give the recipe you used so who knows if it is correct or not. Unfortunately too many folks think that because it is homemade it must be safe to use. Not true. And that if a little is good then a lot must be better. Also not true. Leave it alone and it will outgrow the damage done. Dave

There are two simple observations of unusual formation on leaves: 1. Large, irregular brown spots on surface of camellia leaves, possible facing the sun. It is cause by sun burn. 2. Very dark brown or black formation at leave rim area and tip of the new growth. It is chemical burn, caused by too much fertilizer.

Although there is a huge crowd (mostly people who are on the whole organic gardening train), that believe nutrients need to be in a chelated form to be absorbed into plants. Although that is COMPLETELY correct, their mindset is that rust will stay as rust, but that is completely false. An example people use today is ammonium. Ammonium CANNOT be used by plants in the least bit. It is however converted into nitrates through microorganisms. The same goes for rust. Rust (or Iron III oxide), will either end up chelating to organic acids in the soils (such as humic, fulvic, or acetic). It is there where the oxygen of the rust will combine with the hydrogen in the acids to form water, and the newly freed Iron III ion floats around dissolved in water until is forms an insoluble precipitate via chelation (most likely with the conjugate base that supplied the original hydrogen). It is in this form that it can absorb through the roots. This process is simply accelerated by microorganisms and highly acidic soils. But it is complete BS to say that rusty nails won't help with iron deficient soils, it will just take a lot more time for it to work. And if a plant is already dying from iron deficiency, then it's most likely going to die before it starts absorbing some. That is why it's important to give a dying plant immediate attention with a EDTA or amino chelated form of iron. Or You can dissolve nails (Or better yet, steel wool) in vinegar. You can enjoy this process first hand by placing a fire-stick above the soaking wool and bumping the glass to have the hydrogen bubbles float to the top all at once. It makes cool popping noises. However, your suggestion of Iron Sulfate is no different from rusty nails soaking in sulfuric acid.

I can only give you the same advice as what you'll find in all the other "what is wrong with my tomato plants" posts here. The 'what you need to do' (treatment) is the same regardless of which bacteria or fungus is causing the problem unless it is Late Blight. And since you say the plants look good otherwise I strongly doubt it is Late Blight. Are you using a good fungicide on them as recommended? You should be. Weekly per the label instructions of whichever one you choose to use. Why are you leaving the affected leaves on the plant? That only makes the problem worse and spreads it. They need to be removed as soon as they develop and disposed of out of the garden. How long have the plants had this problem? Is it getting worse or staying the same? Contact your local county AG extension office and ask if Late Blight has been ID'd in your area. If so then that is a good indication of your problem and the plants are quickly lost no matter what you do. If not, then what you do is spray the plants, keep them cleaned of damaged affected leaves, improve the air circulation around and through them, and keep them going with lots of TLC care until you can harvest. Good luck. Dave