Is a potluck wedding reception considered rude?

We are having a simple and casual outdoor ceremony and reception on a farm in October, and would love to have it as a potluck, but worry that people will feel offended if asked to bring food. We will provide drinks, dessert and some barbecue and plan to put together lovely favors for our guests. Our wedding theme has sort of a down home vintage feel and weddings used to always be potluck back in the day. i think it will give an intimate and family feeling. i would appreciate some opinions.