I have been growing hydroponically for a few years now but I am far from and expert or a botanist.
I have been battling something that I believe is “early blight” for several weeks now.
The pattern is pretty clear. You start to notice tiny brown spots near the bottoms of the plants. Then the spots get bigger… the leaf turns yellow and dies. Left unchecked it goes up the plants and ultimately takes all of the leaves.
From what I understand this is a fungal problem but there are a couple of simple things that seem to slow it’s progress.
It’s a generally accepted practice to remove any infected leaves and get them away from the healthy plants. Sometimes this really isnt an option since you be pulling off all of the leaves and that would kill the plant.
I have been using a pump sprayer with 8oz of hydrogen peroxide in a gallon of water. The internet tells me that the H2O2 the spores that are likely trying to spread. Within a couple hours of the Hydrogen Peroxide being exposed to sunlight it breaks down to water and oxygen so it’s food safe.
Another thing that you can do with a pump sprayer is to mix 1 gallon of water with 1 tablespoon of baking soda and a few drops of dish soap. By soaking your plants with this solution it changes the PH of the leaves and the spores dont find the adjusted PH hospitable.
Tags: Common problem, Tomato, tomatoes