When I find those cabbage worms I pick them off by hand and feed their carcasses to the ants. I'm also trying to create a habitat for birds so they can snack on my garden pests. I have bird feeder and am going to work on creating a more hospitable environment for them, including a bird bath and maybe a few bird houses. I've put a few worms in the feeder to let them discover whats on the menu down below. So far so good.
I also went to a near by park where I've seen lot of lady bugs and captured a few. I gently introduced them into my garden and let them feast on my tiny foes. After a few days, they still scuttle around the area where they were placed. I've witnessed them feasting on aphids, its gruesome, but satisfying. Hopefully I can encourage more beneficial predatory insects.