Researchers at the USDA Human Nutrition Center (HNRCA) have found that blueberries rank #1 in antioxidant activity when compared to 40 other fresh fruits and vegetables. Antioxidants help neutralize harmful by-products of metabolism called "free radicals" that can lead to cancer and other age related diseases. Anthocyanin -- the pigment that makes the blueberries blue -- is thought to be responsible for this major health benefit. In another USDA Human Nutrition Center (HNRCA) lab, neuroscientists discovered that feeding blueberries to laboratory rats slowed age-related loss in their mental capacity, a finding that has important implications for humans. Again, the high antioxidant activity of blueberries probably played a role. A one cup serving of blueberries contains 16% DV of fiber. Blueberries are a source of Vitamins A and C, potassium and folate. Blueberries are very low in fat and sodium. Cultivated Highbush blueberries are typically spaced 4 to 4Â½ feet in the row, with 8 to 12 feet between rows. As bushes can get quite large at maturity, many growers find that 10â€“ to 12â€“foot row spacingsâ€”approximately 900 to 1090 plants per acreâ€”are preferable for tractor operations (mowing, harvesting, and spraying). Rabbiteyes are typically spaced at 5 to 8 feet within a row, with 12 to 14 feet between the rows, or 388 to 726 plants per acre. Blueberries do not have extensive root systems. As a result, clean cultivation of row middles to control weeds and to incorporate cover crops is less damaging to blueberries than it is to bramble fruits. Still, it is wise to till no deeper than 3 inches. Similarly, inter-row living mulchesâ€”also called sodded middlesâ€”generally are not competitive with the crop unless the inter-row species are aggressive and invade the rows. Fescue is commonly used in the Mid-South for sodded middles, as are several other grass species.