Disastrous cabbage

As I mentioned in my post about the mystery plant, I had a period of neglecting the garden a bit.  (Fortunately we got rain every other day during that infernal season, otherwise my plants would not have gotten enough water!)

Another result of this neglect has been the carnage in this charming tub of "Baby Chinese Wa Wa Tsai" cabbage:

As you see, this has become the Bug & Slug Motel of my garden. Disgusting.  I should have done something, sprayed garlic mist on the leaves or something.  But not only was I super busy and distracted while this was happening under my nose, I'm not sure any spray would have been very effective, since it just kept raining and raining.  I'm not crying over, uh, ruined cabbage, but I'd like to take a lesson away from this.  Live and learn, right?  What SHOULD I have done?  What should I do next time?

I'm also curious why the cabbage didn't develop into heads.  The leaves stayed loose, as you see.  Isn't there supposed to be a nice compact ball forming in each plant?  That's what the pictures show.  Oh, and I planted seeds for these in March. They were supposed to be mature in 2 months, but in May they were only still half the size they are now.  Geez.

There are days I really feel like a crappy gardener.