Garden digger

Hello,
My 5 month old Cocker Spaniel won't stay out of my garden and he loves to dig up all the dirt and then roll in it!!
When he does this I lead him out by the collar and say "out" but he goes right back in as soon as I leave.
Any tricks on getting him to keep out?

He does it because it feels good! :) Maybe you could make a designated "digging spot" for him. I have a large seperate yard for when my dogs are outside unattended, it's got so many craters it looks like a moonscape.