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We used formula #2 above because it gave the combined milk and potassium bicarb with dish washing fluid combination and provided correct volumes to go by. Wear gloves during treatment or you’ll get some yellowing of your fingers and hands.
We made the mistakes of planting purchased acorn squash which brought the powdery mildew into our garden. We planted too close to watermelon and cucumbers which allowed transfer and we failed to get the plants up off the ground soon enough and watered from above at night, all big mistakes in a first round learning curve.
Watch out for suggestions to use 3% hydrogen peroxide. It seems to migrate into the leaf tissues and affected the watermelon in serious ways.
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Thanks for the tips.
I mistakenly bought some potassium carbonate instead of bicarbonate to deal with powdery mildew on grass… Would it be suitable as well but may need to be diluted with more water? If I understand correctly, we would need carbon dioxide to convert the carbonate to bicarbonate but not sure how to go about it or whether that’s needed.
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Hey James, thanks for your question!
Shopping mishaps – we’ve all been here! Unfortunately, there’s no simple way to change your potassium carbonate into potassium bicarbonate, and it’s not much use around the house either unless you enjoy making your own soaps. It won’t address your powdery mildew problem even if it’s diluted, so it’s best to return the product if possible and purchase the potassium bicarbonate.
We hope that answered your question.
Thanks Ann
Reply Oh shoot… guess we’ll be making some soap then!
I’m curious as to the science behind why carbonate is not effective vs. bicarbonate to effectively treat PM, if you know.
Thanks
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Actually, I have a question. Can I treat the soil with potassium bicarbonate solution prior to planting seeds? I gad powdery mildew on my pumpkins and zucchini
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Hi,
Thank you so much for your question! While you certainly can treat the soil with your bicarbonate solution prior to planting seeds (as this will not harm your plants), the spores generally travel by air and land on the plant’s leaves.
So, while preparing the soil beforehand will be helpful in terms of getting rid of any spores left in the soil, you will still have to keep an eye out for new spores that drift onto your plants and regularly spray them with the bicarbonate solution to minimize any powdery mildew infections in their early stages.
We hope that answers your question!
The Sumo Team
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I purchased some lye water at an Asian grocery. Potassium carbonate and sodium bicarbonate. Can I use this for powdery mildew? If so, what proportions? Thanks.
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Hi,
Thank you for the tips. Could you post the portions (or proportions) needed for #3 please?
Thanks so much!
Hi Andrea,
1 tablespoon of each works brilliantly as a general treatment
So:
– Dishwashing Liquid, 1 tablespoon
– Vegetable Oil, 1 tablespoon
– Potassium Bicarbonate, 1 tablespoon
– Water, 1 gallon
You can add an extra spoon of dish soap if there is an insect infestation as well as mildew.
Good luck!
Kind regards,
Mabel Vasquez – Horticulturalist
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Can a gallon of solution be mixed and then stored in the fridge for further use?
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Hi Belinda,
If you’re using milk in the solution, it’ll keep for as long as the milk will – so I wouldn’t leave it in too long. If you leave milk out the solution would store for longer, but as I understand it, potassium bicarbonate will only break down in water if it’s heated.
Best regards,
Mabel Vasquez – Horticulturalist
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