I bought this in a pre-potted salad mix. It's a tall plant and has a milky stem.
One of the oakleaf types?
"It's a tall plant and has a milky stem."
Sounds like it's bolting! Is it bitter by now?
Doesn't matter what kind it is, once it gets tall and gets that white milky stuff in the stems, it gets bitter.
Looks like arugula rocket lettuce to me.
See the link and scroll down...yes?
Here is a link that might be useful: Arugula Rocket Lettuce/Green
"Bolting" sounds like a good word for it. It's really tall and thin. Not sure if "arugula rocket" fits. But yes, it's bitter. Should I just cut it down to the base and let it re grow?
Bolting means it's done. It wants to make seeds and then die. All of it will be bitter now.
If it is only just starting to bolt I eat it. But then I quite like some bitterness in a lettuce if offset by a good vinaigrette. You can also cook lettuce and early bolters can be braised or made into soup.
So, I am new to this. I have a patio garden that I just started this year. Do I cut down the lettuce now?
Pull it. It's done. You could let it go to flower and seed, which will attract some beneficial insects. But as far as consumption, back to the grocery store or market.
It's not arugula -- when it bolts it makes flowers and seed pods (which are all delicious).
I have cut lettuce down to the base before and had it resprout, but it's probably not worth the space to see if that works. Just plant something else in its space. Summer isn't very good lettuce season anyway.
If lettuce is bolting and it resprouts from the cut stem, it will still be bolting.
Arugula (rocket in the UK) is not a type of lettuce at all. It's in the Brassica family along with cabbages and the like.
You can cut back bolting lettuce and you will get a little more crop but you can't stop it bolting for more than a few days. If you are pushed for space pull it and plant fresh lettuce seed/plants or something else. The bolting habit is why it is sensible to sow lettuce little and often in suitable climates. This is 'succession' planting or sowing. Otherwise it all matures at once and the crop is over.