I am not at home during the day. He also chews everything
he can find.

I also have a 4 month old JRT. I have random chew toys and rawhide bones around my place for her to chew on cause she has a problem with chewing too...we had a big problem with shoes for awhile. She is actually doing allot better now, whenever we find her with something she isn't suppose to have we reprimand her and give her something she is allowed to chew on, her favorite are the rawhide bones, and baseballs.....she doesn't like the tennis balls we got her and she found a baseball in the yard one day and she hasn't left it alone since...

Also, when she fist started going to the things we allowed her to chew on her self we praised her ALLOT!! JRTs are CRAZY for praise and treats!! (we just have a problem with house training now)

Put him in a cage always why your gone. www.abunchofpuppies.com

distract him, buy him a kong and fill it up with the foods that he loves. Another option is to buy him a sand pit and ecourage him to dig in that.

Sprinkling black pepper will discourage him from digging in your garden, it will irritate his mucus membranes and he will NOT like that To stop the destructive behavior when you are not at home, confine him to an area that you have "terrior proofed", or kennel him. You can give him a toy such as a Kong, which can be filled with treats or peanut butter and will entertain him for hours.

as far as the digging , when i got home and found that my dog had been digging i took him back to where he dug and sternly told him, "Bad Dog!!" then i took him over by my garden hose on his leash and tied him to something so he couldn't get away and gave him a good wash down with some water straight from the hose, tied him out again to dry. he hasn't dug since.

Put some hot sause in the holes he dug so when he digs there again he the spicy scent on his nose then thinks that it's going to alway be their and with that nose dont want it to happen again.

If you catch him digging spray him with a water bottle and tell him no. That's what I had to do with my dog now because he was barking at my boyfriend everytime he moved. I just gave a quick squirt and said no in a firm voice. It worked in just a few days.

Give him some regular exercise that will make him tired. Ensure supply of water and shade as well.

You can give him big bone to chew (e.g beef knuckle bone ) and gawn on. This exercises them and keeps them entertained for a long time.

Lastly, you must discipline him each time he tries to dig your garden. Catch him in the act and punish him for it. keep him confined in a safe place (free from toxic stuff he can reach) until he can behave himself is the next best option while training him to stop his habbit.