Rats + Vegetable Garden = nope.
We have been living in the city for two years now (SW Bmore/Violetville) and the rats are barely kept under control by 311/Rat Rub Out. We had wanted to start a vegetable garden last year but decided to wait and improve the soil first. We planted flowers/herbs instead and didn’t really see many issues with rats until this past Fall. A couple burrows that we handled. With us planting a vegetable garden what are the best practices to discourage rats, prevent them from eating and contaminating everything? We also have a small/medium sized dog that genuinely wants to kill the rats. But with 311’s bait stations and poison in the burrows I can’t really let him do more than just bark or urinate to mark his territory in the yard. And he doesn’t poop in the yard at all. We always pick up after him so as to not contribute a food source for rats.
Do everything you can to reduce the rat population. http://extension.umd.edu/hgic/rats
Managing Rats in City Gardens http://www.bbg.org/gardening/article/managing_rats_in_city_gardens
You may want to create an enclosed structure for your vegetable garden. You will have to use hardware cloth underneath. Unless you line your beds with half inch hardware cloth, rats are capable of digging into your vegetable beds. Rats can climb up the structure so you will have to find materials to enclose it.
You may be able to search online for some ideas.
Here is additional information on Norway rats from the Internet Center for Damage Mgmt. There is some information on Rodent Proof Construction/Exclusion http://icwdm.org/handbook/rodents/NorwayRats.asp