I have useed milk and water (40/50) with a dash of baking soda (sodium bicarbonate). I have used it from early on as PREVENTIVE measure not to fight the mildew.

There is an organic product called NEEM OIL. I have use that on diseased cucumbers too. It did pretty much keep the mildew on check. And because it is natural oil, has no restriction on harvest and consumption. I woule buy concentrate and mix my own.

So, the best practice is to use any of the above from early on , once every two weeks on all cucurbia. (cukes, squash, gourds..)

it says to use neem oil castile soap and soduim bicarb and that will rid the problem once and for all but I tried the bicarb alone and the sages which I sprayed turned black two died the other had leaves turn black

I have heard similar stories about using bicarbonates.
Probably it is applied TOO strong. Wit milk and water some do not recommend baking soda at all. Some say like teaspoon per quart.
I have not mixed neem oil by anything else. There are varied home remedies. some also ad a drop or two of dish soap. But I like milk/water. there are also many proportions, starting from 10/90 all the way to 50/50. So I would take the average, i.e. 30/70.

margowicz - are you still trying to grow these herbs indoors? Sage very rarely gets powdery mildew outdoors. It is associated with water stress and if your sage is outside it is less likely to suffer.

I bought this over winter and well we know what our winter was like but since then I have everyting out besides the young plants I leave them on my windowsill as I don't have a green house I put them out on sunny days but no I had rosemary indoors to start and that got the mildew me completely inexperinced didn't think much at the time went got a sage plant it was massive and cheap and I thought it was a real bargain so got it and I think one passed it to the other

whats better to use hotricultre sand or perlite or perhaps both?

whats better to use hotricultre sand or perlite or perhaps both?