Likely too far along to separate them now without losing all of them as the roots would be very entangled by now. So you can either just let them continue as is and get smaller heads or scissor-snip off the extras at the soil line leaving one to continue on.

With purchased transplants it can sometimes be difficult to tell if there is more than 1 plant in a cell. But with cabbage there often is.

Dave

There is nothing wrong with planting cabbage close unless you want large heads. We normally thin them when they are still very small, but sometimes we miss a few and just let them grow together. When this happens we normally harvest a few heads early on and then let the other heads grow more. This usually works for us.

I'd let them go until you get hungry...then selective take one off the group. I'd just let one get to mini veg size - something usable, then harvest.

kmorr; I have a friend that grows all his cabbage,sprouts,broccoli in clusters of 3-5 plants so he can till with a garden tractor with a rear mounted tiller. That way he can cross till and save a lot of labor. I can attest to the fact that the yield is good as I was able to harvest some leftover last fall. If you look up Dutch multi-planting you might find some info. I know you will find onions. Eliot Coleman has some info on this to. It must be in one of his books I can not find it on line.

Curt~