Oi... It was just a typo error; there's no need for everyone to get uber
worked up about the spelling of 'secret base'.
My secret bases (yep, two cartridges!) are both in route 120, just east of Fortree. My first one is in the hollow where it rains a lot - just chop down a tree to find it and a patch for three berrys conveniently positioned next to it! (I don't know if it's just my imagination, but I keep thinking that berrys will grow faster if planted in a frequently raining area...)
My other base is located way down the route, a little south of RegiSteel's tomb. You can't miss it - there's a berry patch for four a couple steps in front! It's not as rainy as my first, but it works all the same.