'Edible gardening' or 'Container' section ??

:thumb: My friend has a little courtyard & she grows in the large black plastic pots that look like florists buckets a bit.. She grows in them in the winter..
Valdor lettuce are big and slow growing. One per florist bucket to grow them to maturity, more if you just want some leaves.

Protovoy. One per florist bucket. One tightly headed cabbage goes a long way, I don't think it's bad for the space as you can eat it all. Keep it covered and even the outermost leaves will be sumptuous.

Kale. One per florist bucket. You can cut and come again, in which case you certainly need five or six, or just grow one or two and cut the whole lot in one go. You can't eat the stem, but most leaves should be edible if it is kept sheltered.

Chard. These can grow very big, but you could squeeze two in a bucket. At their peak, four plants should give you enough for a helping for two. You only pick a few leaves from each at one time.

I think growing in containers involves compromise. Try not to pack too many plants in one pot - you may be disappointed with the total crop... Good luck.. You could start bringing on seeds or plants to plant up in them for winter.. :thumb: