From a good friend who I'll just call Professor CC
"Dyna-Gro Neem Seed Oil is a very fine product and is easily sourced around the country. Unfortunately when discussing neem oils the discussion almost always revolves around a single compound in this oil - Azadirachtin
This is pretty stupid since Azadirachtin is only 1 of 320 compounds found in neem and karanja seed oils. Specifically this compound is a terpenoid - fair enough.
Having said that, Azadirachtin is only one of 20 terpenoids found in neem and karanja trees. It would be like discussing the benefit of eating citrus fruits and simply focusing on Vitamin C - pretty stupid.
The Dyna-Gro Neem Seed Oil is a very fine product and one that I've used for several years. The level of Azadirachtin specifically is 1500 ppm as per the Dyna-Gro company. And it's a cold-pressed oil which retains much of the beneficial compounds vs. the chemical extraction process used on garbage like Azatrol and Azamax.
The neem tree products from The Ahimsa Foundation (NeemResource.com) is organic. The product comes out of Southeast India in the ancient neem groves going back to the 16th Century. The Azadirachtin levels in this specific product is 4500 ppm - i.e. 3x the levels in the Dyna-Gro Neem Seed Oil
It's human food-grade, fair trade and cheap, cheap, cheap. If you hit their web site look at the horizontal menu bar across the page and hit 'Sample Packs' of which there are 3 deals available. All of them a killer pricing.
Here's the mix that I use with their products to completely, totally, absolutely prevent mites, PM, thrips, etc.
1/2 tablespoon of organic neem oil
1/2 tablespoon of organic karanja oil
1 tablespoon of Dyna-Gro Pro-TeKt (liquid silica and is the perfect emulsifier for these oils)
Mix in a 'rock glass' until you get an even solution. Add this in small amounts to 1 gallon of TEPID water (i.e. 65F - 75F) and slowly. Higher temps diminish the effectiveness of these oils. Once you get that done you now need to add a surfactant to make this mix 'stick' to the leaves and branches.
I recommend using liquid yucca extract (again you want to get organic human food-grade meaning no preservatives) - this is available at T & J Enterprises in Spokane, Washington.
Once you have the oils and liquid silica in the spray tank add 1 oz. (2 tablespoons) of the yucca extract. Close the tank and shake as hard as you can to activate the saponins in the yucca extract.
Hit each and every leaf on the top and bottom (especially) until it looks like you haven't watered your plants for a couple of weeks, i.e. leaves hanging down and generally looking pretty sh*tty. Shut down the lights and let them sit in the dark until the next 'on cycle'
Repeat every 4 or 5 days for at least 3 applications. This will break the adult-egg-larva cycle much like dealing with fleas on you dogs and cats perhaps.
If you want you can also use organic aloe vera juice and I add 1.5 ounces (3 tablespoons) to each gallon of the neem/karanja and water mix. George's is a good product and certainly inexpensive enough. It's organic and has NO preservatives. 90% of aloe vera products do use one of the following or all of them: sodium benzoate, citric acid and potassium sorbate. Cute, eh?
Both of these neem and karanja oils are the finest that I have been able to find. If there's anything better I would be happy to check it out, i.e. I'm not closed-minded on this deal.
I can't recommend these products enough and at the price in their sample packs vs. Dyna-Gro and ESPECIALLY the sh*t from a company called 'Einstein Oil' this product provides bottom-basement pricing. Einstein Oil is $65.00 for 1 pint or $520.00 per gallon.
The organic neem oil from The Ahimsa Foundation is around $75.00 per gallon. Heh......... CC"