The onion will gradually lose moisture and eventually deteriorate.
The cloves can remain aromatic for much longer than the fresh onion, but once the onion begins to spoil, the entire arrangement should be discarded.
Check it every day or two.
Don’t wait until the onion is visibly covered in mold.
Fresh produce can deteriorate internally before obvious signs become visible.
Don’t Confuse Odor Masking With Odor Removal
This is an important distinction.
A strong smell can make another smell less noticeable without actually removing the source.
For example, if a kitchen smells like spoiled food, placing cloves nearby might add a strong spicy aroma, but it won’t eliminate the bacteria or spoiled material responsible for the odor.
The correct approach is always to remove the source first.
If there is a bad smell:
Find the source.
Remove spoiled food or waste.
Clean the affected surface.
Wash the container or area.
Improve ventilation.
Then use pleasant aromas if desired.
The onion-and-clove combination can be viewed as an aromatic addition, not a cleaning solution.
What About Mosquitoes?
You may encounter claims that putting cloves in onions will keep mosquitoes away.
This should be treated cautiously.
Certain plant-derived aromatic compounds can have mosquito-repellent properties in laboratory testing, particularly when concentrated in oils or specialized formulations.
But a few cloves stuck into an onion are not equivalent to a tested mosquito repellent.
If mosquitoes are a significant problem, proven measures are more dependable.
These include:
Removing standing water
Using window screens
Wearing appropriate clothing
Using a tested insect repellent
Keeping doors and windows closed or screened
Using appropriate mosquito-control measures around the home
The onion-and-clove trick can be used for its aroma, but it shouldn’t be relied upon for protection from mosquito bites or mosquito-borne diseases.
Can It Keep Cockroaches Away?
Strong smells are sometimes claimed to repel cockroaches.
Clove-derived compounds have shown insecticidal or repellent activity in some laboratory studies, but that doesn’t mean an onion with cloves will eliminate a cockroach infestation.
Cockroaches are primarily controlled by sanitation, exclusion, targeted traps or baits, and appropriate pest management.
If you see repeated cockroach activity, look for:
Food crumbs
Leaking pipes
Moisture
Open garbage
Cracks and gaps
Food stored in accessible containers
Areas behind appliances
A scented onion cannot address these underlying conditions.
Is the Trick Safe?
For most people, simply placing a whole onion with whole cloves on a plate is a low-risk household practice.
Nevertheless, there are a few things to remember.
Keep it away from young children
Whole cloves are small and can present a choking hazard if handled or swallowed by young children.
Keep it away from pets
Pets may investigate unfamiliar objects.
Don’t allow animals to chew the onion or cloves.
Don’t put it directly beside food
Although both ingredients are edible, a deteriorating onion should not be allowed to contaminate food.
Wash your hands afterward
Especially if you have been handling a raw onion or anything that has been sitting in an area exposed to insects.
Avoid concentrated clove oil without understanding its risks
Clove essential oil is much more concentrated than whole cloves.
Concentrated essential oils can irritate the skin and can be harmful if swallowed. They should not be treated as interchangeable with the whole spice.
