So you're buying organic produce from you local grocery or health food store, and chances are if you're buying it from your local grocery store then the majority of those vegetables are coming from one of two major organic food companies located in California. Assuming you don't live on the west coast the question becomes how fresh are they, especially when compared to locally grown organic produce. It is true that relativity speaking California is more local then say New Zealand, Portugal, etc., but if you're not on the west coast then organic or not these vegetables are most likely picked prematurely in order for them to get to your local grocer before they begin to rot.
So they question again is, is there a difference between locally grown and non-locally grown produce?
The answer of course is 100% YES! I experienced this myself this morning when I was snacking on some carrots, a few were from a local organic farm stand that my wife and I frequent often during the summer months, and a few from the organic section of our local grocery store (from some large organic produce company located in California), and what a difference. The funny thing is you don't always notice the difference until you do a side by side comparison. The smaller (less commercial looking) locally grown ones tasted, well, very much like a carrot should, but when I re-tasted the non-locally grown ones I noticed something I hadn't noticed before... they lacked flavor.
As you know it is very important that your diet consist of fresh organic foods, and as you may or may not know it's important that these foods be eaten 'in season' (for instance don't eat tomatoes or blueberries in the dead of winter), but even if you follow these eating guidelines I urge you to go one step further. Find a local organic farm in your area, even if you have to drive an hour to get there, and taste the locally grown difference!