It is very important to remember that not all bugs are bad - in fact many are good. The web site I referenced above will show you which ones are bad and which ones are good. So let those good bugs get in there and have the bad ones for breakfast and lunch and dinner. Not only will other bugs do that for you - toads and frogs, snakes, and birds all feast on bugs. Invite birds in by placing a birdhouse or a birdbath near the garden.
Snakes love the damp rocky areas near the garden.
You can also build a little hut for them. Turn an old planter upside down with a little hole cut out so they can get in it. Try it, it works. While you are there subscribe to Organic Gardening Magazine.