Jerry wrote:

No need to remove the sprinkler heads and cap off the risers. Just
close the adjusting screw on the top of the sprinkler popup.
snip

J.A. Michel wrote:
It should be noted that this would work only if you have popup heads, such
as the RainBird 1800 series or similar. It will not work if you have impact
or gear-drive heads.

Thanks, I have both. If I tighten the gear drive type the screw would
just go all the way through.

Dave FL