Cabbage (from my experience) has to be planted in Dec at the latest and MUST have cold to form heads. I use Copenhagen Market cabbage seed and have always had fabulous results...sometimes the plants in box stores aren't zoned for us. Even if they don't head, the leaves are perfectly edible and of course, taste just like they should. Careful not to wet the leaves when watering, they tend to wilt and then brown. I'm thinking it's probably the plant is not zoned for our heat/humidity... We didn't have any cold to speak of this year..my blueberries didn't even bloom.

How long have they been in place? How far apart did you plant them?

deannac, gotta disagree with you about the correct way to water cabbage. Cabbage plant leaves are perfectly designed to funnel water directly to the center of the plant at the base. Some other plants also grow that way.

Any plants that seem to gather and direct water flow, I water accordingly. I do try to water early in the day so the leaves have ample time to dry.

It must be my horrible well water then. If it rains on the cabbage, it's fine (I know exactly what you mean about the leaves funneling water. Looking at them, you can tell they work exactly the same way a brom would for instance).

Every time I've slacked and used sprinklers on the garden, everything does beautifully except the cabbage. The bottom leaves wilt and then rot...it looks bizarre, fat round cabbages with NO outer leaves, lol...like little green volley balls! This has happened with every variety of cabbage I've ever grown, with the exception of bok choy, which I'm not really fond of...figures.

Thanks for the info...I hate to think that I've given someone information that's not correct!

I lost this post and stumbled over it again.
I am sorry I took so long to reply.
Thanks for all the posts. I have three in a rectangular pot. AThey have been in place now for six weeks or more now and they have huge leaves, are curling in the centre a bit, but not tight. Sometimes they get watered every other day, bz the sun hits them a bit, but all I really have are huge leaves. I am tempted to cut the leaves and use like collards.
It has been hot down here esp some days, and then interspersed with one or two cold days. They are planted about 8" apart, but now that they are big they crowd each othere.

thanks again.

You may have other problems but spacing sounds like a definite one. A mature plant can easily be over 2 foot wide and what you see above ground is only half of the story. The roots need plenty of room too.