Are California veggies bigger? A recipe might call for one large onion or two small eggplants. When cut as directed it seems to yield way more than the recipe intended. I got the two smallest eggplants in the store and after cutting one I had more than enough for the recipe. It almost seems like the people who write the recipes only have access to veggies that are smaller than average. Is there a reason why their large onion is equivalent to my small to medium onion?
The size of the veggies can be due to location only to an extent. If their seasons are longer for cultivation to harvest then the plants may experience better growth.

Other factors can also contribute. The use of fertilizer for example, or if using hormones and pesticides, etc... all effect the outcome in size, quality, taste and possibly even firmness or even color.