Blackwelder column: Cool spring delays fruits
SALISBURY — Last year the unseasonably warm winter produced many tree fruits ahead of schedule. This year, peaches, other tree fruits and the strawberry crops are at least two weeks behind schedule.
Kevin Huffman’s peaches are showing almost a full canopy of blooms, harbingers of fruit for the summer. The unusually cold weather this spring has apparently suppressed growth and development. On a positive note, Huffman reveals the long range forecast does not include cold weather.
Ironically, lack of cold weather is a serious problem for commercial tree fruits. Many high quality peach varieties must have close to 1,000-plus hours of cold weather below 40 degrees to have good fruit set. Last season, many locations throughout the South did not reach proper chilling degree days.
Heavily blooming trees, while very beautiful, can also be a problem later with heavy fruiting. Both peach and apple trees laden with fruit can be a serious problem if not properly thinned. Over-production of blooms is nature’s insurance against late frosts. Astonishingly, a peach tree can lose 90 percent of its blooms and still have an appreciable crop.
Thinning heavily fruited trees prevents unnecessary limb breakage due to excessive weight. Removing the excessive fruit also enhances the taste, color, size and quality of the remaining fruit left on the tree. Thinning allows additional sunlight to penetrate the tree canopy, necessary for carbohydrate production for the next season’s fruit set.
Most fruit trees require 35-50 healthy leaves per fruit for normal development. It is important to note that these leaves must be healthy for the duration of the growing period.
Apples, peaches and pears should be thinned 4 to 6 inches apart. A good rule of thumb is to leave space for one fruit to fit between each side of your hand. Be careful when removing small fruit from spur-type apple and pear trees. Spur-type trees produce buds that bear fruit from the same spur each year. Fruiting spurs are easily damaged or removed during the thinning process. Trees that are diseased, damaged or misshapen should be removed first.
It is also very important to maintain a rigorous spray schedule for fruit trees. Healthy, disease-free leaves are essential for good quality fruit. Fruit trees must be continuously sprayed from flowering until a few days before harvest to keep them pest free and prevent fruit rot. Most fruit diseases are rampant during hot, humid conditions experienced during the summer. Go online to http://www.cals.ncsu.edu/plantpath/extension/clinic/fact_sheets/index.php?do=disease&id=7 for more detailed information.
Darrell Blackwelder is the county extension director with horticulture responsibilities with the North Carolina Cooperative Extension Service in Rowan County. Learn more about Cooperative Extension events and activities by calling 704-216-8970, Facebook or online at www.rowanextension.com