Powdery mildew on pumpkin leaves

I read about baking powder and water mixed up and sprayed on the leaves directly in the evening then rinsed of in the mornings is supposed to clear it up, not tried it myself yet though


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You need sodium bicarbonate (it is in baking powder but that also contains cream of tarter), oil and pure soap Controlling or Eliminating Powdery Mildew - Growing A Greener World TV . It does work but will probably need repeating. I would remove the worst affected leaves, ie those that are dying off and/or totally covered. Spray what's left carefully on both sides of all the leaves. It is worth giving the plants a nitrogen feed to boost those leaves that are left so they keep filling the pumpkins you have. At this stage of the season, don't let the plants set any more pumpkins. If the plants recover, it's probably worth giving them tomato type feeds to help fill the fruit.

At times during this summer my cucumber and pumpkin plants have started to build up high amounts of powdery mildew, so I looked around online on how to deal with it.

I decided on a method that used potassium bicarbonate, horticultural oil and plant soap. At first I too was going to use sodium bicarbonate(baking powder), but then I read that the sodium is harmful to the soil and potassium does everything just as well if not better, i.e. potassium helps in fruit growth as an added bonus.

I used it on the plants and noticed almost immediate results. The powdery mildew dried out within a day just leaving some faint white marks and after that it was gone completely. Of course it comes back in a couple of weeks if the weather has been humid and you just spray again.

Only thing you need to watch out for is to make sure you keep the sprayer bottle you're using shaked up nearly constantly, otherwise the oil and soap floats to the top and the bicarbonate to the bottom and then you seem to get a high concentration of bicarbonate on the leaves which can turn them black/kill them.

Make sure the plants have plenty of moisture at the roots, not on the leaves, it helps the plant to resist the mildew.

I use a copper sulphate and magnesium solution which works well for me.