You can help keep squirrels out of your garden and deter the squirrels from your garden by adding a layer of mulch around the plants.
Also set a motion activated sprinkler out near your garden and when the motion activated sprinkler detects the squirrel or other animal the sprinkler will come on and spray the squirrel or other animal with water and they will run away.
The water will also water your garden so you deter the squirrels and also water your garden some at the same time.
You can also use some fine mesh wire or chicken wire around your garden to help keep the squirrels out of your garden.
However the squirrel can still climb the wire if they are determined but the wire around the garden will help keep the squirrel out.
Or install an electric fence around the garden and when the squirrels get near the fence they will get shocked and will either run away or die.
Yes squirrels can climb wire.
Squirrels are very good climbers and climb just about anything including wire, fence wire etc and can walk across wires on poles.
Squirrels are also very good at jumping up on things and can jump four feet straight up, leap 10 feet laterally, and they can climb just about anything.
If you have a garden and want to keep squirrels away from the garden plants you should use some fine mesh wire around the plants and also add a top to the wire above the plants to completely enclose the plants from the squirrel.
The plants will still be able to grow but the squirrels won't be able to get through to the plants through the wire.
Also if you have bird feeders that you're hanging up and want to prevent squirrels from getting to those bird feeders you should hang the bird feeders between trees.