Holes in Cabbage?
Probably means they are being attacked by cabbage worms.
Homemade Organic Spray is great for the problem. This is a very easy and natural way to get the worms off.
Homemade Garden Spray
In a Food Processor, or blender process 1 onion 3 garlic cloves, 3 hot peppers until they are mushy and somewhat liquid like. Next add 1 quart of water, and let steep for 1 hour. Strain with a cheesecloth or fine strainer. Add 1 T. dish washing liquid, mix well and then add to sprayer. Spray leaves making sure you get the underneath side too. Repeat every week or two.