While roaches are a troublesome pest, some of the most common means of repelling them contain harsh chemicals and poisons that are nearly as bad to have around as the bugs themselves. If you want to repel roaches through safer, gentler and more organic means, there are a variety of plants that these insects are naturally inclined to avoid. Use plants as a green yet effective means of helping to keep your home roach free.
Catnip is not only one of the most effective deterrents against roaches in the plant kingdom, it's one of the best roach repellents available across the board. In the late 1990s, researchers at Iowa State University determined that the smell of catnip is 100 times as effective in repelling cockroaches as DEET, the active chemical in heavy-duty insect repellents. A major benefit of catnip as a repellent is that you can use it in its fresh or dried form, or you can brew a tea from the dried plant and spray it in areas where cockroaches have been sighted.
Bay leaf, a stiff, large leaf used to flavor slow-cooked savory dishes, has a mild smell to humans but is abhorrent to roaches. This spice is available in any grocery store with a spice section and is useful for deterring cockroaches around areas like baseboards, cracks in walls and beneath appliances. Grind up bay leaves using a mortal and pestle, or grind into a fine powder using a coffee grinder.
The pungent aroma of garlic bulbs is one that repels many insects, and cockroaches are no exception. The most effective form of garlic has the strongest smell: fresh, minced cloves. However, fresh garlic is also a smell that many humans don't enjoy in their homes, so if you want something milder, sprinkle garlic powder to keep the roaches away.
Despite their deceptive name, hedge apples aren't fit for consumption, though they are often sold in grocery store produce sections. Hedge apples are about the size of large oranges and are green and covered in bumps. They are grown and sold expressly for the purpose of repelling insects and their smell will help keep roaches away. Take care, though, to always replace your hedge apples when they start to go soft and brown; rotten hedge apples can attract other types of insects.
Roaches dislike the smell of cucumbers. The most effective way to use cucumbers to deter roaches is to leave cucumber peelings where roaches can smell them, since the peelings are juicy and give off more odor than a whole cucumber. Though you may not like the idea of leaving cucumber peelings lying around, try making it a habit to prepare cucumbers on a regular basis so that the smell of cucumbers and peelings in the trash will help discourage the bugs.