Having found a rat's burrow in or near your garden is cause for concern. Norway rats are burrowers and known for ravenous appetites. They are omnivorous and will just as happily feast on your garden edibles as on goodies from the compost pile or garbage from the bin. Burrows are generally up to three inches in diameter, near a dependable water source, and smooth around the edges from heavy traffic. Norway rats like to burrow near house foundations or under stones such as along patios or garden walkways.
Set out traps or bait to attempt to catch the rat or rats before plugging the hole. Setting out unbaited traps for a few days and then baited but not set, for a few more days, greatly increases your chances of successfully capturing a wary rat. There are many trapping and baiting options available at home improvement stores, department stores and garden centres.
Flood the burrow using a water hose if you have no success with baiting or trapping. Even if you have caught a rat or two, there may be more in the burrow. Flooding may help by drowning rats, or evacuating them.
Fill the opening of the burrow with dirt to successfully plug it.
Many Norway rat burrows have an emergency exit or two. They are often concealed, loosely covered with soil or hidden in grasses or weeds. When flooding a burrow, keep a sharp eye out for escapees, and be sure to fill in those exits, as well.
Be careful setting out traps or baits, or using rodenticides if you have small children, pets or livestock that might come into contact with them. Always take precautions, follow user instructions carefully, and practice good containment to keep animals and children out of the area while using.