Sprinkle Baking Soda on Cabbages (and other Brassicas) to Thwart Caterpillars If those small green cabbage worms have been making Swiss cheese of your cabbage, broccoli, and kale plants, try this trick:
Make a 50/50 combination of flour and baking soda, and dust it all over whichever plants the cabbage worms are eating. They'll eat the combo while munching the leaves, and die within a day or so. Repeat as necessary.
Controlling Cabbage Worms
Reviewed by Gardener