Most likely cabbage loopers as they are the most common cabbage pests and they eat round holes in the leaves. Use Bt to kill them.

Dave

Here is a link that might be useful: Cabbage Loopers

Thanks Dave. Anyone else know of other ways to get rid of the critters? Or what else it could have been? b/c as I said I never saw anything on the leaves, just the holes.

If it's not cabbage loopers, it could be slugs. You wouldn't see them unless you were out there at night with a flashlight.

How do you combat them, slugs and worms I mean. Do you sprinkle with Seven Dust or use organic methods? I'm growing collards and mine are being eaten away by slugs. I've dusted them with DE but the rain keeps washing it away. I'd really prefer a more natural way of combating them if possible. Thanks

For cabbage loopers you treat with Bt dust (Bacillus thuringiensis) it is organic and readily available.

For slugs there are numerous baits on the market - one of the most commonly recommended is Sluggo sold at most any garden center including Walmart.

A search here will pull up numerous discussions for you on both pests and a wide range of recommended treatments.

Dave

Another organic option for cabbage (and all cole crops) is to keep them covered with row covers that serve as a barrier to the butterflies that lay the eggs that hatch into the little green worms. Really works and is really easy. Just keep it tight at the edges.

Thanks everyone. Happy cabbage to ya!