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.
Store the cucumber peel in your refrigerator until it is rotted. Rotted peels will attract them since they are attracted to rotting food.
Place the rotting peels in areas where you've noticed the cockroaches, such as behind appliances or inside the cabinetry.
Sprinkle the rotted cucumber peel with Diatomaceous earth. This product is composed of bits of soil with tiny, sharp edges. These sharp edges will irritate the roach's exoskeleton and cause it to dehydrate. While some forms of diatomaceous earth are benign, several types have silica that could cause silicosis if inhaled. For safety, wear gloves and avoid breathing the powder. Keep the product away from pets and children or surfaces that they frequently touch.