There are many products on the market that claim 'neem' as an ingredient. Often, the 'neem' is combined with other insecticides and a vehicle that makes emulsification and thus delivery/application easier. If these products have used neem oil that was altered or obtained by a process other than cold-pressing, the value or effectiveness of the essential ingredient azadirachtin has likely been reduced or negated entirely. I have read reports in these & other forums about growers using products like Bio-Neem by Bonide (and others) and having less than what they consider stellar results, while I continue to use the cold-pressed product, such as is produced by Dyna-Gro, with what I consider very safe and very good results. Remember that neem oil doesn't deliver a huge initial knockdown punch, but it IS a powerful antifeedant and chemosterilizer, rendering current generations unable to feed or progress through metamorphic stages to adulthood, and rendering adults sterile. Cold-pressed neem oil is excellent on mites & works initially in the same way as hort oils work, with the added benefits of the other properties already noted. This from a recent post @ another forum site: "As I consider the prophylactic use of any insecticide, including systemics, I guess I have to say that about the only compound that fits that description for me is neem oil. I over-winter around 100 tropical plants (most are normally grown as houseplants, but my focus is on bonsai) under lights in my basement. About 2 weeks before bring them in, I apply neem oil - then again a day or two before I bring them in. Normally these applications keep insect levels in check all winter, though I may see some scale or mite populations appearing toward winter's tail. If it gets too bad, I'll do a neem application & hold out until I get the plants outdoors where the increase in the plant's metabolism and thus natural defenses, along with the increase in beneficial predators, usually completely eliminates the trouble. The bio-compounds plants use to repel plants are a by-product of the plant's metabolism. Plants with high energy reserves and plants growing with good vitality are much better protected 'naturally' from insect predation, which is why plants in low light and those that are just limping along are far more likely to be troubled by insects. I very often diagnose the occurrence of insect infestations as the end product of poor cultural conditions, and the greatest, most frequent offender is a poor soil." I'm not implying you're using a poor soil; I know you're not, but others might wish to consider the corollary. Al

I'm no expert, but I do seem to remember in the one report I read about neem (Azadirachta indica) trees, the plants around them were still eaten by insects. Plus, all that foliage will negatively effect the amount of sunlight your veggies will receive, so I'd stick with the spray.

I'd dispute the contention that neem oil/extracts are more toxic than fatty acid-based insecticidal soaps. ANY substance, organic or not, can be toxic if applied in great enough concentrations. Neem has been used as an herbal remedy and dietary supplement by populations in its natural locale for centuries with documented beneficial effects. The big advantage to neem oil over other organic controls is its adaptability for numerous purposes, as both an insecticide and fungicide and as an effective control of other disease pathogens. There is a very scholarly article on the pros and cons of neem oil/extracts available online, however it requires membership to the site or payment to download and view. A google search with the key words "neem oil, harmful side effects" should turn it up. Otherwise the attached is a good, well-rounded treatise on this organic control. Here is a link that might be useful: Neem oil

It's popular because it only takes two to three applications to kill nearly everything, Kevin. And, there is evidence the active ingredient is absorbed by some plant roots as well. It isn't a simple oil and water solution either, the recommended formulation requires a surfactant like certain soaps so that they mix together better and can be applied more evenly instead of separate large globs of liquid. I haven't had to deal with pests on fuzzy or hairy succulents but I don't think I'll have problems using neem oil spray on those either. It certainly beats having to use systemic pesticides every time something alarming comes up. Donning the hazmat-esque wardrobe alone is a PITA. But I bet you've read that too lol