Question: what to do if there are rats in the garden?
Answer: Peppermint oil. Rats hate the smell of peppermint oil, so it's an effective way to drive them away. ... 
Catnip. Get some catnip from a garden centre and plant it in several spots around the garden. ... 
Keep your garden clean. ... 
Remove food and water sources. ... 
Soil netting. ... 
Sealing gaps.