German cockroaches are nocturnal; they come out at night seeking food and water. However, if you have a severe infestation, you may see them in the daytime as well. To keep German roaches away from you while you sleep, keep food and water out of your bedroom. Also, clear the clutter from your bedroom, and empty your bedroom trash bin regularly. The best way to keep German roaches away at night, it to treat them with bait and thoroughly clean and sanitize the kitchen and bathrooms.