When is the winter cut of northern grapes
In the northern region, winter pruning of grapes is a key operation that determines annual production in the coming years. Scientific pruning can not only enhance the tree's cold resistance, but also optimize nutrient allocation and reserve sufficient energy for spring germination. This article will combine illustrations to analyze in detail the best timing and operating points for winter cutting of northern grapes. 1. Control of winter pruning time for grapes in the north 1.1 The best pruning period for climatic conditions and phenological periods is after falling leaves to before the soil is frozen, specifically from late October to mid-to-late November. At this time, the grapes have completed nutrient backflow, the flow of tree sap slows down, and the pruned wound heals quickly. If the operation is done too early, secondary growth may be easily caused, and the bleeding phenomenon will be exacerbated after the night. 1.2 Special cultivation precautions must be completed for greenhouse planting before mulch covering. It is recommended to cooperate with soil cultivation and cold protection measures in areas covered with mulch covering. Alpine regions can be advanced to mid-October, and warm winter years can be delayed by 7-10 days. 2. Standardized operations for grape pruning 2.1 Tool preparation and disinfection Use professional pruning shears, and the edges must be kept sharp. Disinfect with 75% alcohol every 3-5 plants after pruning to prevent the spread of bacteria. Healing agent should be applied to incisions with a diameter greater than 2 cm. 2.2 Three-dimensional pruning skills ① Longitudinal pruning: Keep 4-6 buds for strong branches, 2-3 buds for moderate branches, and remove weak branches at all roots.② Horizontal pruning: Keep the spacing between main vines>50cm, and the spacing between main branches 30-40cm.③ Three-dimensional pruning: Leave more new branches in the lower part of the frame surface, and properly control the height of the upper part. 2.3 Standardize the handling of key positions and make a 45° oblique angle between the cutting edges and the bud eyes to ensure that the cutting edges face the outside of the frame surface. Double-bud branches retain outer lateral buds to avoid crossing branches and vines. The single branch renewal method is used for perennial old vines to retain the basal buds. 2.4 Bud density control calculates the amount of buds retained according to the surface area of the frame: 20-25 buds are retained per square meter on the hedge frame, and 15-18 buds are retained on the scaffold. Dry farming areas reduce the number of buds retained by 30%, and fertile areas can increase the number of prepared branches by 20%. 3. The special tree pruning plan adjusts the strategy for different tree ages: young trees are mainly cultivated for skeletons, and trees over 3 years old are pruned with a mixture of long and short shoots. Plants that encounter freezing damage need to retain 50% of the spare buds, and weak trees should be subjected to heavy pruning and retraction.
Scientific winter shearing is the cornerstone of high-quality and high-yield grapes. Mastering the three principles of "pruning by the sky, leaving buds by the ground, and fixing branches by the tree", combined with the illustrated operations in this paper, the grapes in the north can safely winter and achieve stable production year after year. It is recommended that growers establish pruning files and optimize pruning plans year by year.