hey there LotsofBeautiful , you know, outdoors is outdoors so there's a limit to what you can do, like you're never going to be able to prevent bugs from coming on these plants. What you can do is basically control the outbreak to the point where it's there but it's not a problem. So what you need to do is assure there is a sort of "food-chain" or " microbial-insect-matrix " that keeps the bug numbers down and doesnt hurt your plant. I always recommend using beneficial bacteria because it doesnt damage the plant like neem oil which changes the taste, but it does take a little bit longer to be effective. Try adding bacilus thuriengiensis israelis which is a beneficial bacteria that paracites eggs larvae and adult bugs and in doing so controls their spread and reduces the infestation. For infestation management you want to combine spraying with adding it to the waterings, so make sure you spray around sunset, light degrades the bacterial spores. Usually you can get the infestation under control between 10 to 14 days with this method, and after that you're just topping up. It sounds like an advanced technique but it's actually quite common place so dont be scared to ask for this stuff in your garden center . Hope this helps ! π