Quote Originally Posted by OakLeaf View Post
I've had excellent results with Mildew Cure. It pretty much eradicates powdery mildew on all my cucurbits. It's OMRI listed, but the downside is that it's based on cottonseed oil (30%) which is not organically grown, therefore grown with extremely toxic chemicals; it also contains garlic oil (23%) and clove oil (30%) for which the oil base isn't listed on the label, but Johnny's catalog suggests it's corn oil, which again, is not organic and therefore extremely likely to be GMO.

The Mildew Cure label lists sodium bicarbonate as an inert ingredient; but after I bought it three years ago (it works really well and goes a long way!) I've seen lots of recipes for mildew control using baking soda and hort oil only, and studies confirming that it's effective. Typical recipes call for 3-4 tsp of baking soda and 2-2.5 tbsp of horticultural oil (any lightweight vegetable oil - corn or safflower e.g.) in a gallon of water. Sometimes they'll add 1/2 tsp of dish soap as a surfactant as well.
I've read similar concotion at an organic gardening web site. My concern is that where I live so close to the ocean and arid climate, any addition of sodium to the soil is not a good thing. sodium bicarb isn't all that different than potassium bicarb so I'm thinking maybe its the Na+ or K+ that's killing the mildew.

What's really interesting is that mildew is only affecting just small portion of my garden while the rest are healthy green. Sooo how can a strain of plant is free on one area and overwhelmed in another area.

Anyway, I'm going to be testing for NPK in the bad area and also in the good part. Maybe this will tell.

Oh potassium carb can be had at a local ceramic store under potash. Sodium carb is listed as soda ash. The difference between carb and bicarb in this application is their solubility I think. It's not the carb or bicarb that is killing the mildew.

anyway if you know more I would love to hear from you. I just the problem to be resolved.

smilingcat