Squirrels and chipmunks dig up everything I plant
Honest answer first: these two are close to unexcludable at property scale. The winning move is protecting individual things rather than trying to secure an area.
What actually works
Lay ½-inch mesh over newly sown beds and bulb plantings and pin it down. Seedlings grow through; diggers can't get started. Lift it once plants are established.
Plant the bulb inside a basket of mesh. It's fiddly once and permanent after.
Half of all squirrel 'damage' is one bite out of a tomato on the day before you'd have picked it. Pick at first blush and ripen inside.
Not against these. They climb everything, and a fence that stops a squirrel is a fence with a roof — which is a cage over one bed, which is the first item on this list.
Also searched as
squirrels in garden · chipmunks eating bulbs · squirrels digging pots · squirrel proof · chipmunk damage · animals digging up seeds