After losing several lettuce plants to cutworms severing the stem completely in my garden, I wanted to find a good & inexpensive collar. These Lil Red shot cups are the perfect size for plant starts that are started in the smaller version of seed starter cells.
It works out to less than a quarter each, and these are reusable.
One modification I am going to try is to have a vertical slit so I can remove the collar when the lettuce is big enough that a cutworm won’t be able to kill it. I’m concerned about disturbing the roots too much by removing it though.
The collar is wide enough that the lettuce stem might be okay growing in the collar until it is harvested. It might not.
I have two of each type of lettuce I am growing in this batch, so I think for one of each type I will leave the collar on, and the other I will remove it when it is mature enough and see if there is a difference in growth.