I'm not sure you'd get rid of rats with herbs. But I'd be interested to hear more about it, too.
A rat has been trying to get into our house for the last few days. There is only 1 tiny hole in the whole place, and we covered it with cardboard and put a heavy bottle on top. It neatly ate all the cardboard and kept knocking at the bottle. Very noisy at night, I can tell you.
There is now fly screen to cover the hole with the heavy bottle on top. It hasn't eaten the fly screen (yet?) but still keeps knocking at the bottle.
I am sure it would very happily eat any herbs I put there. I might stuff steel wool down the hole. This helped with all the other areas where mice/rats entered before.

May the pied piper be with you! :)

Hi,
we had rat troubles in our old house and found that 'Space Invador', a spray-in foam which hardens and becomes solid, did the trick of blocking up holes. Buy it from hardware stores - just tell them you want the spray-in foam that blocks holes.
They are pretty pesky - one night a rat got into the house by pushing off the kitchen extractor fan (which had a chimney as a flue)and climbed into the house.
It made such a noise I was sure a burgular had broken in.
I went to investigate and was actually pleased to find a rat rather than an intruder.
When I replaced the fan the next day I stuck it down extra tight.
Deryn

I also would be interested to see if anyone has a solution to rats and mice. We have them digging our seeds out of the ground and eating them. Its a real bugger to come back the morning after a long day planting and find all the shells of the seeds lying around the ground.....

Hi yes I'd be very interested in knowing how to deter rats, I too don't want to kill them. I did try some mint in a cupb but did'nt really help, I heard camphor deters possums so it may deter rats. Will keep watching for any ideas.

Can't help with the repellant, but an interesting anecdote:

We had rats in an old house that we used to live in. The rats used to escape traps and eat the baits to no effect!
One day my husband came into the kitchen looking rather shaken. He said a rat had just walked boldly into the loungeroom, stood under one of the chairs and just stared at him. Later that day we were sitting in the lounge room when we saw a currawong land on the fence outside the window. It sat there a moment, then made a dive for the ground, and reappeared on the fence with a rat dangling from its beak. It then proceeded to tear it apart.
Perhaps we all need more currawongs.

Get a bigger more vicious cat.

I vote for more currawongs

Don't be kind to rats, they are a pest and damaging not only to gardens but to the environment. If you have rats you have a moral obligation to make sure they are dead. End of story.

I have read that rats dislike mints including catmint, in contrast they are attracted to valarian root, so it might help to bait your traps with it.

My dog has dealt with any rats we've had in the past (and one mouse but they're usually a bit small). You don't know any friendly Jack Russell terriers who can come and stay for a few days?

(with a note that rats do carry nasties & can put a fight, so if a pet cat or dog does have a run in with one, check them for injuries afterwards)

Just ensure it's not a native ratty thing, in which case you may exercise prejudice and not kill it (they're a little smaller and have white underbellies with a greyish top and are just as common in the inner city as the disease-carrying nasty ones).

Pennyroyal works for cockroaches, that I know (and, it appears, snails ... I found dead ones on my fresh growing herbs. No karma on my conscience on that one!!). There's a brand of oil-infused papers called "Go away friends" that has scents to repel moths, ants, cockroaches ... and I _thought_ I saw rats among them, but I could be wrong.

I have a rat problem too out in the garden, so am trying to find a solution, saw somewhere where you can put down some cement or plaster of paris and some water they eat it and it sets inside their bellies and they die constipated. Don't feel sorry for rats they breed disease, dirty buggers. If you have any holes in your house or gaps stuff heaps of Industrial steel wool into them, that is a great solution for rats and mice trying to get into your house, they can't eat through it, stops them all the time.

I don't think mint would deter them, I don't know about herb mints but my pet rat steals my polos and mentos out of my bag and I find her crunching away on them in her cage.
If you want to trap the rats in cages I'd suggest chocolate, otherwise I'd say get a cat, or better yet a ferret. -plus ferrret urine should keep away rats anyway because of the smell