How do I stop 4 month old pup digging up garden?

Veruca Salt has realised she has joined a family which at one time had coal miners, she has decided to walk in their shoes, well to dig rather than walk ?

that wasn't very helpful, sorry.

Both my poodle crosses dug holes in the garden if given the opportunity. I think the key is not to give them the opportunity, taking them out on a long lead as you did is a good way to stop them practicing. The more dogs repeat a behaviour, the more they seem programmed to do it. Nip it in the bud. Digging is fun so of course they want to do it. Don't let them but do provide other excitement like chasing and retrieving a ball. I found both mine loved 'find it". Id teach them to sit/wait then hide something in the garden for them to find. The digging didn't continue and they can now go into the garden without destroying it. Good luck

Our spaniel used to try to dig holes in the sofa and/or the carpet if left alone to 'guard the house' for a while.
He eventually stopped but took to rolling in cow pats instead.

Mine was a digger, never had one before, absolute caverns in the lawn, thankfully he grew out of it at about year old but I do understand the mud and general ruin of the garden

Well I say UM in a very stern voice, and he stops all the time I’m looking at him!!

When you find out Smurf52 let me know please, I've spent 13 years trying to stop my JR digging holes. We love him though.

There was a pet programme that suggested making an area where she may dig, I think they made a little sandbox/pit and buried treats so it was confined. Would that be possible?