Hydrogen Peroxide On Powdery Mildew

[GoDawgs]

I found the beginnings of powdery mildew at the bottom of the pea vines and one small patch of something that might look like a virus or other. Not seen that one before. I had a faint recall of information about using hydrogen peroxide on mildews so I checked my archive of saved gardening articles and sure enough. I have researched this before but never did anything with it but have now started an experiment.

Monday evening I sprayed the peas with a diluted peroxide solution, hoping to wipe out the mildew that has started and see if it checks the other mischief. It's a three day course of treatment. If it works it could help all of us with an environmentally friendly solution for many plant troubles and peroxide is very inexpensive. More on this later.

Several links for your reading on this if you're interested:

https://homeguides.sfgate.com/hydrogen-peroxide-plant-fungus-86713.html

https://www.therustedgarden.com/blogs/vegetable-gardening-tips-blog/how-to-use-hydrogen-peroxide-on-your-tomato-plants-mix-ratios-spray-routine-theory

[jmsieglaff]

Your H2O2 solution sounds promising!

I use Potassium Bicarbonate + a few drops of dish soap in water for powdery mildew--it works great. I mix 4 tsp potassium bicarbonate per gallon of water with the few drops of dish soap. I get it from my homebrewing/wine making shop, it's much cheaper to buy it from them than a gardening source, lol.

[mama_lor]

I have used it last year. It is best to use it with acetic acid (preferably in a certain proportion) to achieve some amount of peroxyacetic acid which is supposedly even stronger antifungal. I can't say it helped visibly, but the conditions were very bad.

[Growing Coastal]

I have used hydrogen peroxide to slow down PM in the past. A grower told me that it works best as a preventative. The same is said of sulphur which I am using on garlic rust this year and I am spraying the few plants with PM with that (potted mini roses and pansies).
No PM yet on the tomatoes but it has shown up very early this year in a dry spring with just enough rain to create humidity.

[Cole_Robbie]

Here is what the trendy cannabis growers are using these days to fight pm.

https://www.canr.msu.edu/news/regalia_a ... se_control

[GoDawgs]

Your H2O2 solution sounds promising!

I use Potassium Bicarbonate + a few drops of dish soap in water for powdery mildew--it works great. I mix 4 tsp potassium bicarbonate per gallon of water with the few drops of dish soap. I get it from my homebrewing/wine making shop, it's much cheaper to buy it from them than a gardening source, lol.

Thanks for that. I think the only homebrew shop went out of business but I'll check around. Do you use it for prevention or after PM appears? Right now I'm using the low end of the dilution scale as suggested, which is 2 TBS per quart. Tonight will be the third of the three days of treatment. Next spring I'll start spraying earlier.

This year I tried to keep every bit of henbit out of the peas because when henbit's at the end of its run, it will immediately funk up with PM and that spreads to the peas. The onset of PM was a bit later this year, maybe because of the henbit supression. Or maybe the weather. Who knows. Too many variables to account for.

[MissS]

Here is what the trendy cannabis growers are using these days to fight pm.

https://www.canr.msu.edu/news/regalia_a ... se_control

I have learned a lot from the cannabis growers. Those guys really know their stuff and take their growing seriously.

[pepperhead212]

I saw a number of articles by cannabis growers for the harpin protein, when I was researching that.

[jmsieglaff]

Thanks for that. I think the only homebrew shop went out of business but I'll check around. Do you use it for prevention or after PM appears? Right now I'm using the low end of the dilution scale as suggested, which is 2 TBS per quart. Tonight will be the third of the three days of treatment. Next spring I'll start spraying earlier.

This year I tried to keep every bit of henbit out of the peas because when henbit's at the end of its run, it will immediately funk up with PM and that spreads to the peas. The onset of PM was a bit later this year, maybe because of the henbit supression. Or maybe the weather. Who knows. Too many variables to account for.

It is best as a prevention, but I have had success killing PM after noticing it on my squash/zucchini leaves. If I wait until it's bad it is not curative, but I have had success killing PM back at the start of infection and then reapplication a few days later.

[Cole_Robbie]

I just found this recipe for fermented horsetail weed tea as a fungicide. It looks easy and virtually free.

https://www.nature-and-garden.com/garde ... l-tea.html

[Mark_Thompson]

Brother is a weed grower so we went halves on a big jug of Regalia. I’m unimpressed after using it for a year. Just my opinion, take it for what it’s worth.

[bower]

I've been trying to control the weeds that host the mildews, but it's a tall order. The pink clover, the purple vetch, forgetmenots, and I saw some on a white clover this year as well. I don't mind nixing the forgetmenots but all those N fixing weeds are bee favorites too. So I beat them back around the greenhouse windows as well as I can, but let them be in other parts of the garden. I've never seen mildew on peas here. It only gets bad when we have a spell of hot and humid weather. So I guess it must be tough to battle in Georgia!
I do have a yellow clover here that seems immune to mildew. It's a creeper and self seeds profusely too. Not a nice weed but okay for the paths. Unfortunately, the bees don't show any interest in those little yellow clovers.

[brownrexx]

My squash get PM in the late summer and when I planted fall peas they got it too so it seems to be present around here in late summer when it is hot during the day and cool and sometimes humid at night. Late Blight on tomatoes likes this type of weather too.

I have used sodium bicarbonate (baking soda) mixed with water and sprayed it on the plants. It raises the pH of the leaf's surface and makes it unsuitable for PM growth but it does not kill existing fungus and it does wash off with rain.

It has been worthwhile in allowing me to get late season squash. I have never tried hydrogen peroxide.