Yes, each stem is an individual plant. Either snip the weaker ones and plant an individual plant, or plant them all together and see what happens. Or do some of both.
They would be more than happy in cut-down milk jugs - with drainage. Put the holes a few inches up from the bottom - of you put the holes on the bottom, and they’re sitting on a solid surface, they won’t drain properly.
That goes for bigger pots/planters, too. You don’t want plants getting water-logged. ;)
Noted & thanks! I might try separating a couple to see what happens - I usually get away with that with tomatoes when I buy those 6-packs and get maybe 10 plants instead!
(For tomatoes I separate, repot, let ‘em recover and grow several days, then do the transfer to a partially shaded outdoor spot for a few days, then finally plant ‘em in the garden.)
To not get the lettuce cooked after mid-May, I’ll try putting the lettuce “pots” on the north side of our house. I’ll have to put up a little wire fencing to keep the chickens out of that spot! I “might” also try again in our basement, but that didn’t go well last year. I do have a stronger light there now though (9k lumens).