Many pests are easily dealt with.
To eradicate slugs, place an empty butter container or similar item into the ground in your garden up to the rim. Fill it about half way with beer. The slugs, attracted to the beer, will fall in and drown.
If you have cockroaches, place cinnamon around any areas where you want specific protection. Cockroaches do not like cinnamon, and will avoid any area where they smell it. Fortunately, cinnamon sticks can be arranged in a decorative fashion for a less conspicuous solution. Also, you can use candles and air fresheners that use or simulate real cinnamon.
To keep many pests, including stray cats, mice, squirrels, rabbits, and insects away from your garden, sprinkle mothballs all around the garden. If they stick out too much, cover them with a bit of mulch and/or place them very close to the base of large plants. If there is a great amount of direct rainfall into the garden, however, the mothballs may dissolve quickly and could harm your plants, so use sparingly.