How Densely Can We Plant Apples?

This is a question many have asked over the last decade or so. Many growers have thought about it and some in the Great Lakes Region have actually committed to plantings that are in the super spindle class. From a horticultural perspective, you can make a very tight planting work. Economically, there are limitations as to the amount we can invest in an acre of new orchard.

The costs of establishment can pile up quickly; with trees and components that are needed on a tree by tree basis being a major cost factor. However, density of planting does not have as great an effect on other major inputs such as irrigation and something like hail netting.

When you talk about spacings of 1.5 to 2 feet (super spindle) it translates into 45 cm to 60 cm in row spacing. The plant material alone for this density of planting could amount to several thousand dollars per acre or more (if it is sourced off the farm.)

In a recent discussion of super spindle and high-density systems at the Great Lakes Fruit Workers Conference in Michigan, New York researcher, Dr. Terrence Robinson summarized his findings on this type of system.

The tighter you plant, the faster you get returns. At some point, "the less densely planted orchards catch up to the super spindle with yields". With the super spindle, the owner should carry the planting for a minimum of 20 years to capture reasonable profits. In other words "you cannot grow super spindle for less than 10 years and expect to make money". Also the concept of super spindle is more attractive if you have the ability to produce your own nursery trees, since this can significantly reduce costs.

Another issue is light distribution within the high density planting. "The fruit colour disappears as the system matures" according to Terrence (if you are growing a cultivar with a colour requirement).

Terrence Robinson felt that a spacing of 4-5 feet in the row and 12 -13 feet between rows provides a good compromise. He emphasized that when you plant tightly you have to be very sure of the cultivar choice and growth habit.

In conclusion, an ideal cultivar for ultra high-density production should be grower friendly, have a high output of fruiting wood and provide good yield efficiency.

However, more importantly the variety must have consumer demand and pay well. The ultimate challenge is to get the best potential variety into the right system, at a manageable and affordable planting density.