Thread: bleach spray
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Old June 8, 2013   #5
b54red's Avatar
Join Date: Sep 2009
Location: Alabama
Posts: 6,622

Originally Posted by amideutch View Post
Bill, so what your saying is if I spray a healthy plant with diluted beach as a preventative nothing will happen to the plant and will have no effect on it what so ever.


You are basically correct except it isn't a preventative. If there is no type of fungus or disease for it to react with nothing happens as long as the mix is not too strong and not sprayed in direct sunlight. I don't spray plants showing no signs of disease unless we have had a long rainy spell in which case I know some disease is there despite not being able to see it. I frequently spray my seedlings before they are potted up with a fine mist if they look like they may be getting some disease symptoms. The younger the plant the more sensitive it is so when spraying seedlings I use a milder solution. Plants that have been hardened off and are in the outdoors can be sprayed with the regular mix with no ill effects that I have been able to see. Bleach at full strength or at a high concentration will dissolve cellulose so of course if you spray plants with a very strong solution a lot of damage would be done to them. When I first started experimenting with this I consulted two chemist friends about it and both were of the opinion if I could find a solution that was strong enough to kill diseases without damaging the healthy growth that it would work. I wasn't sure when I began that I would find that happy balance. I started out with a solution way too strong and got a good bit of leaf burn then next went to one that was so weak it didn't kill enough of the diseases to be worth using. It took a lot of trial and error experimenting before I found that happy medium. There are a few diseases that are more difficult to control and I sometimes get my mix a little strong when dealing with them and get some leaf burn on healthy tissue. I would rather have a little leaf burn than a dead plant so in those cases it isn't much of a trade off. The big trade off is when you wait too long and allow diseases to take over a plant before using it. If you use it then you are going to lose a lot of foliage and there might not be enough healthy plant left to be worth the trouble.

I doubt I would have ever gone to the trouble to learn how to use this with all the experimenting that I had to do if I lived where the disease pressure was more moderate. It is a result of total frustration with all the products that are out there that supposedly help with tomato leaf diseases. I tried nearly all of them with limited success but with a much lighter wallet. I finally tried what I found by pure accident while cleaning mildew off my house one summer. I was using a 20% solution of bleach and rinsing it off and got a bunch of it on a climbing rose that was riddled with spot diseases. I tried rinsing it off with fresh water when I realized so much had hit the plant but the next day half the leaves were gone. A few days later I noticed that the leaves that fell off were the ones with spots and the others were fine. That summer was the best that rose had looked in years. That was the far too strong solution I used first on a tomato plant riddled with Early Blight and Powdery Mildew. Anyway that is how it got started for me and I'm happy it did every tomato season.

All of my plants in those pictures were sprayed from the very top to the bottom every time I treated them with no harm to the new growth and healthy leaves. Many of the lower leaves were diseased. I have already had to battle a bit of Early Blight, Powdery Mildew and Gray Mold so the infected leaves either withered up or had enough dead spots on them a few days after spraying that I went ahead and removed them. Had I not sprayed many of those plants would now be near death because many diseases just keep going up the plant at a rapid rate if nothing is done to stop it in my hot and humid climate. Two years ago I lost nearly a third of my plants by this time to Gray Mold because I waited too long and kept expecting the fungicides I was using to stop it from spreading but they did not. I had to learn that lesson like most I have learned the hard way. Now if at all possible I will spray a plant the afternoon of discovering active disease on the plant. I still use fungicides and they are a big help especially when it isn't too rainy and humid and that would probably be enough in a lot of places to keep plants fairly disease free.

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