This post is in continuation of the previous post on Training Systems in Intensive Apple Cultivation: Trellis. This post explains about the Slender Spindle training system further modification of spindle bush training system.
This is the system preferred by growers who wish to work exclusively from the ground and are not confident in building wire support systems. The slender spindle (SS) consists of an individual support post at every tree.
Slender Spindle Support System:
The post should be 2.4 - 3 m in length and of pressure-treated wood, concrete or metal to ensure it lasts the life of the orchard (perhaps 12 - 18 years). A diameter of 4 - 6 cm is preferred, since risk of frost heaving increases with larger diameters. The depth of the post in the ground should be 60 - 90 cm for stability leaving 1.5 to 2.5 m above ground. A common mistake is to have insufficient post height above ground.
Slender Spindle Training Pruning:
The tree is trained to a slender bell, or pear shape with the bottom whirl of branches acting as a permanent fruiting table. The leader and top of the tree is kept quite weak to contain height. Renewal pruning of mature trees consists mainly of removing 2 - 3 of the largest diameter branches on an annual basis during the dormant season. Tree height does not exceed 2 - 2.5 m.
In the next post I shall be discussing about the Vertical Axis or French Axis training system. This system is followed mainly in France having average productivity of about 42 Tonnes per Ha.