How can I stop my dog from getting in my plants?

I have put a large pot plant base under my bird feeder and that stops the seeds from falling on the ground

You can spray some pungent white vinegar around your plants. The scent should be enough to keep him away.

I use hardware cloth. I cut it to fit the pot and then cut a slit and opening in the middle for the plant.

When the dog starts to dig, he will get stopped by the wire mesh. It is invisible when you cover it lightly with dirt.

you essentially have 2 choices. You can either make the plant inaccessible to the dog (move or fence the plant) or train your dog to stay away from the plant. There are a bunch of way to approach the training solution. Consult an experienced trainer near you to determine the best approach for you and your dog. Some trainers will give free advice over the phone. Also p note that citronella is generally an adversive to dogs. You can either buy several citronella (mosquito) candles and apply the wax liberally around the perimeter of your plants or go to the pet store and purchase a citronella spray that you can apply to the perimeter of your garden.

sprinkle cayenne pepper on the soil they hate the smell.

Moth Balls they hate the smell!!!