Onions are a powerful natural repellent for rats, according to experts from Epic Gardening and Buzz Boss. The pungent aroma of onions is enough to make rats flee a garden, with one expert noting that rats "hate them".
Lorin Mielsen from Epic Gardening said that placing an onion where rats are suspected to be entering will cause them to "take one smell and run out of your garden". However, the onion must be swapped out every couple of days to prevent it from rotting.
Why onions work
The specialists at Buzz Boss described onions as a "cooking staple that's a nemesis of rats". They explained that onions contain sulphur compounds that irritate the eyes and nose of rats, as well as allicin, which can cause anaemia and oxygen deprivation if ingested.
Buzz Boss recommends growing your own onions in the garden to ensure a steady supply. Onions are a cool-season crop that grow well from seeds, sets, or transplants, and thrive in bright sunlight and nutrient-rich, well-watered soil. Harvest time comes when the bulbs reach full size and the tops turn yellow and flop over.
Other deterrents and risks
Planting garlic along the edges of garden beds is an alternative method that deters a wide range of unwanted visitors, not just rats.
Rats are attracted to gardens by food sources such as dropped fruit, vegetable plots, compost heaps, and bird tables, as well as shelter in thick bushes, outbuildings, and timber stacks. They can cause damage by eating plants and leaving droppings, and they carry diseases including leptospirosis, salmonella, and hantavirus. Their breeding rates are described as alarming, so swift action is advised if rodents are spotted.
