I am in zone 10 in Miami, FL and my sprinkler heads often get knocked out or
damaged by lawn mowers.

I got a few landscape guys to take a look and they proposed two methods to
solve it.

One proposed trenching deeper and reseating the sprinkler pipe deeper, and
thus burying the sprinkler head and let it be flushed with the ground level.
This means they have to trench six inches deeper for over 400 feet of pipes.

Second one proposed leaving the pipes where they are, but instead of
connecting the sprinker head to the threaded end on top of the pipe, to use
an elbow and funny pipe to bury a new sprinkler head 6 inches deep some
distance from the line.

The second method is much cheaper because not much digging is involved, but
I wonder if the lawn mower will knock off the elbow instead of the sprinker
heads?

Any comments? I really would like to get rid of those ugly concrete donuts
around each sprinkler head.

MC