The cicadas will love your young vegetation, so you may want to
protect with an insect cover or wait to plant the lettuce until
august.

As I understand it, periodic cicadas feed almost exclusively on young tree
branches and twigs. I don't think your lettuce is as risk from them,
although slugs and earwigs may end up being your nemesis.

17 years ago, on the eve of the last go round of the 17 year cicadas, we had
lots of young trees and saplings. We purchased a huge roll of black plastic
netting, that made a bit of a dent in the budget of young homeowners, with
the intent of protecting our tree investments. Well, the cicadas came, but
were a bit of a bust in our locale.....we only saw a few, and they didn't
seem to touch our saplings. We still have most of the roll of netting, and
I have learned to relax considerably when in the face of presumed disasters.

Cheers,
Sue
--

Zone 6, South-central PA