Mr. @
Chronic Monster! What's this, you actin' like a noob or sumptin', wot? You started one of my favorite threads, 'overpriced nutrients' YEARS ago, I'm still reapin' da benefits from that one!
To rid yourself of powdery mildew without Eagle20, you'll need a multi pronged plan of attack; this is also known as IPM, aka Integrated Pest Management. The idea is to switch up the mode of attack too fast for the pest to keep up, so each successive wave, while perhaps not strong enough alone, will beat it down and defeat it. Here are some different things to do, in no particular order;
1. Safer 3 in 1 or Safer Soap. These are actually insecticides, but they're effective against PM
2. H²O² - Use this at about 3-5% as a foliar spray
3. Horticultural oil, like
Azamax- if you have a bug problem, this stuff is good for double duty. It coats the leaves, protecting them from PM- It's also good for reducing wilt in very dry conditions, something to consider if you can't get your humidity up into the sixties where it needs to be for best growth. While we're on the subject of humidity, I want to kill the notion- again- that high humidity causes or encourage Powdery Mildew. Not True! The shit thrives on plants stressed by DRY conditions, one reason it's such a plague in the arid West of the US! Explains why raising your humidity is on this list.
4. Ground up aspirin and potassium bicarbonate- the aspirin is an immunity booster and the bicarb raises pH while providing a plant nutrient (K), high pH on the leaf surface makes life tough for PM. This is the same as milk, only better for the plants. Drink your own milk, lol
5. Make sure you have good air circulation and fans blowing air across your plants
6. Increase grow room temps to 100f for a couple of hours, taking care to raise or maintain humidity
7. Maintain good humidity levels for VPD; that means at least 65% and even 70-75% if you're running temps in the 80s. Higher humidity makes for stronger plants more able to resist and fight off disease, PM included.
All of these strategies are at least partially effective, and just as importantly they have different modes of action, or methods to kill or harass the target pest. Doing one of these more than twice in a row usually won't get you as good results, so switch around and find three or four that work for you and rotate among them. As you saw, it's easy to combine PM attacks with pesticide applications, and they can be combined with nutritive foliar sprays as well.
