Q.Container cabbage
I’m helping my daughter grow a container cabbage for The Bonnie Cabbage Program. The cabbage now appears to have split into two separate plants, but I don’t know if this is normal. We want the biggest cabbage head possible, so I don’t want two plants crowding each other. Should I attempt to split these, or is this the way it’s supposed to look?

Certified GKH Gardening Expert
If you do attempt to split them, it may cause damage to the root system. It will grow like that, but they will not produce well if left like this. If you do split them up, expect a pretty long recovery before they start to grow again. If you choose to kill one off, then you will want to cut it at the base, and leave the root system there. This will avoid any damage to the plant that you are keeping.
Here is an article that will help you: https://www.gardeningknowhow.com/edible/vegetables/cabbage/growing-cabbage-in-pots.htm