From the time I moved to Charlotte in 2005 to now, the quantity and quality of the local farmers' markets have improved dramatically.
The Matthews Community Farmers' Market is a beautiful thing, with a fair number of local organic farmers. From spring to fall, the Matthews market is open only on Saturdays beginning at 7:15 a.m. I really doesn't matter much when it closes, because most of the quality produce is gone by 8 a.m., so you need to get up and get there early. The last few beautiful mornings that I have been there, there are large lines. Matthews may be starting to exceed its capacity.
The largest area farmers market is the Charlotte Regional Farmers' Market, a state owned facility. Its a large place, with multiple sheds selling everything from local organic produce to produce that has been trucked in. It is open every day, but most local farmers are there on Saturday morning starting at 8 a.m. Most local farmers are gone by noon. Although the quality at times may not be quite as good as the Matthews market, there is a much greater variety. There is even a rancher that sells fresh (not frozen) pasture raised beef (Underwood Farms).
Why the farmers markets? I buy food at the farmers markets that I will not buy at the grocery. Strawberry are only available in a few short weeks in May and June at the farmers markets--they are much smaller and more delicate than the strawberries you can get at the mega mart, which an intense sweet flavor. Blueberries are the same: small and intense, not large flavorless and pale.
More on farmers markets as the season goes along.