What is the best time to prune apple trees?
Surely many people have eaten apples. People often say “An apple a day keeps the doctor away”, which shows that eating apples brings many benefits to the human body. In the north, many people grow apples. You should know that for apples to grow well, the branches must be pruned, and this will also greatly increase the economic lifespan of the apple tree.
When to prune apple trees
Winter is the dormant period for apple trees. The focus of orchard management is winter pruning, and in combination with winter pruning, diseased branches and insect-infested branches are cut off, and coarse and old bark is scraped off, to reduce or eliminate overwintering pests and diseases.
Tips for pruning apple trees
1. For apple trees that are strong on top and weak at the bottom, a competitive branch from the lower part of the canopy can be used as the leader to extend, keeping the extension at a small angle to promote the growth of the lower branches. For the middle and upper branches, increase the extension angle, and select and keep a downward-facing branch as the extension branch, to balance the tree vigor.
2. For apple trees that are weak on top and strong at the bottom, the lower branches can be extended at a wide angle with a branch behind them as the leader to weaken the growth vigor, while the upper branches can be extended at a small angle with an upward-facing branch as the leader to promote vigorous growth.
3. For young apple trees and trees that have just begun to bear fruit, pruning should use weak branches as the leaders to control the vegetative growth of the tree, increase the accumulation of nutrients in the tree, and promote flower formation. Ring girdling and other flow-blocking measures can also be carried out on auxiliary branches to promote flowering.
4. After apple trees enter the full fruit-bearing period, because of the large amount of fruit produced, the tree vigor is very likely to weaken. When pruning, heading back and renewal pruning should be used more often to strengthen vegetative growth and prevent the tree vigor from weakening. An appropriate amount of flower retention can also be used to strengthen the tree vigor.
5. For crossing branches within the apple tree canopy, cut one branch back and leave one branch unpruned. When rows cross each other, both rows should be cut back, so as to leave working aisles and improve ventilation and light conditions.
Apple tree training and pruning indicators
1. Tree height: for dwarf rootstock trees, trunk height 0.8-1.0 m, tree height 3.0-3.5 m; for standard rootstock trees, trunk height 1.0-1.5 m, tree height 2.5-3.0 m. Trees within a row should not touch each other, and a 1-1.5 m working passage should be kept between rows, with a canopy coverage rate of 75%.
2. Branch number: after pruning, about 80,000 branches per mu should be left on apple trees, of which medium and short branches account for 70%, and the rate of terminal flower branches accounts for about 30%.
3. Branch groups: in the early stage of the open-center form, the main focus is on cultivating small and medium-sized branch groups, with emphasis on selecting all kinds of branch groups that are slanted or facing downward on the main branches, and then year by year cultivating them into large, three-dimensional, downward-hanging fruiting branch clusters. For the spindle form, the small main branches are borne in the state of branch groups, with an open angle.
Benefits of pruning apple trees
1. Earlier fruiting and a longer economic lifespan. Pruning apple trees can effectively regulate the growth amount and extension direction of branches, which helps improve the light conditions of the tree and the accumulation and distribution of nutrients, and shortens the juvenile period, thereby regulating the growth and development of the fruit tree and promoting flower formation and fruiting.
2. Improving the light conditions of the tree. Training and pruning can improve the efficiency of photosynthesis in fruit trees. For example, choosing a suitable tree shape, opening the angle of the scaffold branches, appropriately reducing the number of scaffold branches, and lowering tree height and leaf canopy thickness can all improve light conditions and increase effective leaf area. Then, by reasonably increasing fertilizer and water, improving leaf quality and the photosynthetic efficiency of leaves, and prolonging the photosynthesis time, the accumulation of photosynthetic products can be increased, which is beneficial to flower formation and fruiting.
3. Improving tree nutrition. Training and pruning can improve the metabolic capacity of the tree and improve tree nutrition. The content of nitrogen and water in the tissues of pruned parts is much higher than in unpruned parts, while the content of starch and sugar in pruned branches is lower than in the control. This shows that pruning changes the nutritional composition in the branches of the fruit tree, and this change is beneficial to flower bud formation and to increasing early yield.
Apple pruning can be carried out in any season, but winter pruning is the best choice. This can not only reduce the incidence of pests and diseases the following year, but also improve the growth of the apple tree the next year. There are also many little tricks to pruning apple trees. When pruning, we should follow the principle of weakening but not strengthening.