Will putting a penny or copper rods in the soil stop blight?
I've read on various websites how copper is or can be effective in preventing blight from infecting tomato plants. I've seen people cut into branches of tomato plants and place a penny of infected plants. I'd prefer not to cut into any of my plants. What about burying copper pennies in the soil of the pots? Would that be of any benefit to the plants at all? If not I read that mixing water with baking soda and spraying the plants helps keep blight off them as well.
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rainbowgardener
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I dunno... copper sulfate and other copper compounds are recognized fungicides in spray form. This thing about the copper is all over the interweb, mostly in the form of pushing a copper wire through the base of the stem. I doubt that would hurt the plant. Whether it will really prevent blight is another question. All of the places I found this mentioned were strictly anecdotes and rumors, no scientific studies. I really doubt putting the wire in the soil will accomplish anything, but then I'm not sure the wire in the stem does either.
However, I did find this one place: After each plant has been treated with the copper wire, then fill a spray bottle with 3 percent undiluted hydrogen peroxide. Mist each plant with this solution once a week.
The hydrogen peroxide is a common treatment for fungal diseases by itself. So I imagine if you were spraying your plants with it weekly, you would probably not have fungal problems, with or without the wire.
The baking soda solution is another commonly recommended treatment. The third one is diluted milk. Any of these (or any other fungicide) works better as prevention than treatment. Once a fungal disease is well established, it is very difficult to get ahead of it. Spray your plants weekly. You can alternate treatments.
It also helps to only water the soil, not the leaves, and to mulch well around the plants to help prevent soil from splashing up.
However, I did find this one place: After each plant has been treated with the copper wire, then fill a spray bottle with 3 percent undiluted hydrogen peroxide. Mist each plant with this solution once a week.
The hydrogen peroxide is a common treatment for fungal diseases by itself. So I imagine if you were spraying your plants with it weekly, you would probably not have fungal problems, with or without the wire.
The baking soda solution is another commonly recommended treatment. The third one is diluted milk. Any of these (or any other fungicide) works better as prevention than treatment. Once a fungal disease is well established, it is very difficult to get ahead of it. Spray your plants weekly. You can alternate treatments.
It also helps to only water the soil, not the leaves, and to mulch well around the plants to help prevent soil from splashing up.
Can you change the weather? The best choice for me has been to take off all the lower leaves since they get infected first and mulch. I also live in a humid climate so I have to select for disease resistance and I trellis the tomatoes and keep them as open as possible to get good air movement . When weather conditions are condusive to fungal growth you have to do preventive fungal sprays. Especially if you have prolonged rain. Fungal issues will crop up in the 3 days following the rain as the ground dries out. I usually have to spray after the rain stops. If it rains again then I have to spray again every 3 days for as long as the humid conditions last. Also take out any leaves you don't need or even start to look like they might be getting fungal or bacterial issues.
So it is safe to spray tomato plants (small or big?) with 3% hydrogen peroxide such as the kind you buy from Wal-Mart in the brown bottles for under a dollar and also safe to spray with baking soda mixed in water? I have a bag of Bob's Red Mills baking soda I could use for that. These treatments should only be done once a week right? And do I spray the entire plant? Thanks for the information. I greatly appreciate it!
Sounds like bad folklore (penny/copper rod). To prevent blight, which infects leaves as well (as the stem in some cases), it needs to be sprayed on the leaves, which is commonly done as an organic fungicide. It needs to be in contact. I don't think it is taken up by the plant (and if it is, excess copper can be toxic to both plants and animals.)
Also it depends on what is meant by "blight". Late blight starts at the top and early blight at the bottom. And there are a whole host of other diseases commonly misrepresented as "blight".
Also it depends on what is meant by "blight". Late blight starts at the top and early blight at the bottom. And there are a whole host of other diseases commonly misrepresented as "blight".
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rainbowgardener
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Yes it is safe to spray with hydrogen peroxide straight out of the bottle or to spray with baking soda solution or diluted milk, but one at a time, not together. The baking soda solution would be 1 TBSP baking soda, + 1 tsp salad oil in a gallon of water. You spray the whole plant including undersides of leaves.
I prefer to use sulfur instead of hydrogen peroxide. They are both fungicidal but sulfur lasts a little longer and has a broader spectrum. But it cannot be used is temperatures exceed 85 degrees or within a couple of weeks before or after an oil.
Neem oil can be used proactively as a fungicide. Actually any horticultural oil works by making the leaves more waterproof. Like sulfur, oils can burn plants if temperatures exceed 85 degrees.
Chlorothalanil and Dithane are commercial fungicides that are registered for tomatoes, but I only use them as a last resort.
Baking soda acts as a dessicant and it alters the pH of the leaf.
I like milk as a preventive antifungal spray for mildew which is usually my bigger problem with tomatoes and "hairy" crops like cucumbers and squash. 40% milk and 60% water is a good mix as long as you get good coverage of the upper and lower surfaces of the leaf. I do like to add a tablespoon of oil to a gallon of the mix as a sticker. Don't save any leftover solution and wash out the container with a good degreasing soap like dawn or purple power.
I forgot to mention that drip irrigation and avoiding overhead irrigation especially late in the day helps prevent fungal diseases in general.
Neem oil can be used proactively as a fungicide. Actually any horticultural oil works by making the leaves more waterproof. Like sulfur, oils can burn plants if temperatures exceed 85 degrees.
Chlorothalanil and Dithane are commercial fungicides that are registered for tomatoes, but I only use them as a last resort.
Baking soda acts as a dessicant and it alters the pH of the leaf.
I like milk as a preventive antifungal spray for mildew which is usually my bigger problem with tomatoes and "hairy" crops like cucumbers and squash. 40% milk and 60% water is a good mix as long as you get good coverage of the upper and lower surfaces of the leaf. I do like to add a tablespoon of oil to a gallon of the mix as a sticker. Don't save any leftover solution and wash out the container with a good degreasing soap like dawn or purple power.
I forgot to mention that drip irrigation and avoiding overhead irrigation especially late in the day helps prevent fungal diseases in general.