Block the Holes With Mesh or Chicken Wire
Try to avoid using caulk or plastic or paper to block rat holes; the rats will easily chew through these types of barriers. You can use wire mesh or even chicken wire to block the holes and this will prevent the rats from re-entering the hole.
Dry ice in particular is very effective for outdoor rat control. When placed into rat burrows, dry ice sublimates into carbon dioxide which fills the burrow and suffocates any rats inside. New York City officials started using this method in 2018 to exterminate large numbers of rats infesting public parks.
So, what does a rat hole look like? The entrance to a rat's burrow is typically 2 to 4 inches across. Active burrows have smooth walls and the dirt is hard-packed with loose dirt fanning out at the entrance. The entrance will also be clear of debris and spider webs.
While rats might leave a nest temporarily if disturbed, they will likely only nest somewhere else close by, no doubt creating multiple nests that exacerbate the issue. On top of that, there's also a risk that they will return to the same space if you haven't properly dealt with the nest.
Seal any holes you find to stop rodents from entering. Fill small holes with steel wool. Put caulk around the steel wool to keep it in place or use spray foam. Use lath screen or lath metal, cement, hardware cloth, or metal sheeting to fix larger holes.
Sometimes you might want to flush out the burrow first to force out any rats inside. You can do that by using a hose to fill the burrow with water. This stops the rats inside from digging new holes after you've close them. Don't attempt to fill the burrow with dry ice, poison, or bleach to kill the rats inside.
Rats typically burrow down about 18 inches to nest (if they can't find an indoor home), but they are capable of digging much deeper if a foundation is in the way and they think food is on the other side. Predator pee probably isn't going to stop them. But your mention of steel wool and concrete is on the right track.
"Rats can certainly gnaw through concrete and metal, most normally soft metals such as tin, aluminium, copper and lead, but I have seen gnaw marks on steel, various hard plastics such as waste pipes and terracotta pipes — as well as concrete walls." Alice Sinia, an entomologist and technical advisor with pest control ...
A nest inside a home will usually feature roughly 5-10 rats but it needs to be understood that there can be multiple nests with multiple colonies of both young rats and adults.
All you need to do is mix 2 – 2 and a half cups of ammonia, 100 – 200 mL of water and a 2-3 spoonful of detergent in a bowl. Then, put it to places where rats are usually seen. The smell of ammonia is very pungent that it instantly kills rats.
Essential oils are some of the best natural rat repellents. Rats have a highly developed sense of smell, which makes strong odors such as pine oil, cinnamon oil, and even peppermint oil offensive to them. Cayenne pepper, cloves, and a mixture of vinegar and ammonia will keep rats away as well.
Rats, like mice, can squeeze through impossibly small gaps (anything down to the size of a 10p coin) and should never be underestimated as to their versatility and persistence when trying to enter a building.
Steel wool is a great way to block the small holes pests use to enter your home. First off, steel wool is tough but flexible; it can be pushed into all shapes and sizes of cracks and crevices. Pests like rats and mice hate chewing through steel wool, since the sharp edges hurt them the more they try to chew.
Rats can easily chew through softer materials like cardboard and plastic. They can even chew through harder things like wood and PVC pipes. But rats cannot chew through steel. They can't chew through anything stronger than iron.
There is usually one main entrance and 1 or 2 other entrances which may be less obvious or concealed. These additional exit holes enable the rats to quickly escape if they sense danger. Often, a burrow contains more than one rat. As the rat family expands, the burrow becomes larger with more tunnels and rooms.
Rats are afraid of human activity, mostly because humans are so much larger than they are. Rats also fear predators such as hawks, eagles, and other birds of prey. Other animals that rats are afraid of include your cat as well as rat terriers and other dogs that hunt rodents. Rats fear becoming a meal for a snake.
Rats like to nest near food and water, in kitchens and basements. They build their tunnels so they can reach their food in relative safety. As a nocturnal species, rats are mostly active at night and at dawn or dusk. They come out when the sun sets, then hide in their nests during the day.
Peppermint Oil
On a cotton ball use no more than 5 drops of 100% peppermint essential oil. Spread the oil on areas that you want rats to avoid, in your case, around the garden.
Rats cannot survive with more than 70 to 75 grams (0.16 lbs) of salt in their bodies. Any additional amount of salt can cause severe neurological problems such as muscle paralysis, deafness, blindness, and overall weakness. This is in addition to ailments like gastroenteritis and general inflammation of the system.
A really dilute solution of dettol shouldnt hurt but should stink enough to keep rats out - but I am still a bit cautious about spraying even highly diluted acid anywhere around my engine. I had faced the same problem with my Swift, where the building rats had chewed through a whole bunch of wires.