Mild soapy water takes care of many garden pests. I haven't grown outside but do have a decent herb/vegetable garden and lots of roses. I use Dr. Bronner's with water (Not much, just a few teaspoons per gallon) and spray, make sure to get up under the leaves. I get one of those 1-gallon hand-pump sprayers with a wand that makes it way easier to do the undersides of plants. Once a week, then closer to harvest spray well with water just to get any soap residue off.