Cucumbers are among a handful of natural remedies for roaches. Sliced, fresh cucumbers will deter roaches from an area since they are not attracted to fresh food. That's a good thing, kind of. What's better is dead roaches. If you want to use cucumber peels to kill cockroaches, you will need to let the cucumbers age and cover them with a natural killer, diatomaceous earth. Then be prepared to sweep and clean up dead roaches from the area.