Orchard Design

When deciding how to design a new orchard, there are several questions growers should ask prior to planting trees. The answers to these questions will guide decision making about what size trees are desirable; how many trees to plant; how trees, rows, and alleys should be spaced or oriented; and ultimately lead growers to an orchard layout that will fit their goals and desires for producing apples. For general information on establishing an orchard, visit WSU Tree Fruit site.

What are your goals for growing apples?

Your goals for growing apples are critical for informing orchard design. Do you want standard-sized trees spaced 20 feet apart to provide a lasting source of apples and romance for generations to come? Or, do you want to see quick returns on your investment by planting a high-density orchard that wil likely need to be replaced in 15-20 years? Do you want to grow mostly dessert apples or cider apples? Answering these questions will allow you to determine what rootstock and cultivars are appropriate for your goals and how your orchard should be designed in terms of tree density and training system to achieve these goals. These goals and desires must also be balanced with consumer demand for your end product.

How many trees can you manage?

While you might have 40 acres of good ground to plant an orchard, it is important to be realistic about how that orchard will be maintained and who will maintain it. Any Montana fruit grower and will tell you that good labor is hard to find, and often, growers are pruning, spraying and harvesting their orchards with little additional help. Determining the size of an orchard that one person (or a family) can reasonably manage is challenging to calculate, as the efficiency of orchard management will depend on factors such as tree density, equipment, and grower skill. In general, 10 acres is considered a manageable orchard size for viable commercial production with minimal hired labor (University of Minnesota, 2018). As scale increases, so will efficiency, but additional labor—and thus labor management—will be needed.

How do you want to manage your orchard?

Whether you want to manage your orchard organically or with conventional measures is an important decision to make prior to planting trees. In addition to personal preferences, what the market desires and the price of conventional vs. organic fruit may influence this decision. According to Montana food distributors, the demand for organically-grown fruit is higher than for conventionally-grown local fruit. Organic fruit also demands a higher price, but producing it often comes at a higher price as well. Other considerations include weed, pest, and disease pressure and available options for controlling these issues. For example, an orchard site with noxious perennial weeds such as quack grass and Canada thistle, might be better served to deal with these issues using herbicides when the orchard is being established and delay certification until later in production to give young trees a chance to compete. To learn more about the organic certification process in Montana visit the Montana Department of Agriculture's Organic Program website. WSU also has several resources for growers considering or practicing organic management.

Choosing a Training System

There are several training system options used around the world for producing apples, ranging from the old-fashioned standard trees planted at 50 trees per acre, to the modern high density tall spindle form planted at a density greater than 1000 trees per acre. A general idea of tree spacing, densities, years to bear fruit, and other information about common training systems can be found in Table 1. Which system a grower chooses will depend on their goals. If commercial production is the focus, research has shown that higher density plantings equate to quicker and higher yields over the life-time of the orchard (Fig. 1). While these high-density systems when managed well are more efficient, produce higher quality fruit and yield higher profits, initial upfront costs per acre for installation are much higher as they require trellises and more trees are planted per acre. In addition these systems require skilled management to train the trees and manage them for pests and diseases.;

Note: table adapted from Intensive Orchard Management, by Bruce H. Barritt, Good Fruit Grower, Yakima, Wash., 1992

Figure 1: Increasing tree density has been shown to result in earlier yields and higher mature yields. These data assume a well-managed system and are not from Montana orchards.

Orchard Floor Management Systems

Selection of an appropriate orchard floor management system will depend largely on the training system, rootstock, overall management strategy, and site. Research has shown that vegetation in rows can compete with trees for water and nutrients, resulting in lower yields and smaller fruit, particularly early on (Atucha, et al. 2011 Hoagland, et al. 2008; Merwin and Ray, 1997 Merwin and Stiles 1994). However, depending on your site's soil, slope, aspect and other features, a cover crop can be important—at least in alleys—to protect soil from erosion, compaction and provide equipment access to the orchard under wet conditions. This article from the Intermountain Tree Fruit Production Guide offers a good comparison of the advantages and disadvantages of various ground cover systems.

The type of vegetation selected for use in alleys or the entire orchard floor also depends on orchard design, site and management. Several options are available, from sod-forming grasses to legumes with various advantages and disadvantages that should be considered. For example, while legumes might increase nitrogen, the availability and timing of this nitrogen cannot be controlled and could result in increased susceptibility of trees to winter injury or fire blight. Some legumes have also been reported to attract rodents that feed on their roots. If tree competition is a concern, a good option may be a grass like hard fescue that is shallowly rooted and goes dormant during the peak growing season. Insect pests like spider mites, however, might find trees a tastier option in situations where cover crops are dry and trees are succulent. For more information on choosing vegetation for orchard floor cover, visit WSU's Orchard Floor Management guide and the Intermountain Tree Fruit Production Guides Cover Crop pages.

Row Spacing and Orientation

Once determining how you want your orchard to look, there are a few guidelines for making your orchard successful. Orchards are organized into rows and alleys with spacing between trees in rows and between rows dependent on rootstock and tree height. Ideally, rows are oriented N-S to capture the most sunlight through the growing season. The distance between rows can be determined based on the mature height of trees. At the northern latitude of most Montana orchard sites, rows should be approximately 90% of tree mature tree height. For example, if trees will be trained to no higher than 9 ft, rows should be spaced 10 ft apart (Ontario Apple Growers, 2015). If the orchard is located on a slope, this distance should be increased one to two feet to reduce potential for shading.

The of equipment used to manage the orchard should also be considered, particularly when the end of a row is reached and equipment must pivot. This turnaround space needs to be accounted for at the end of rows and between obstacles like fencing or irrigation lines. Row length should be kept to under 500 ft to maximize efficiency within the orchard.

Spacing of trees will depend on rootstock, tree density and management system. Cultivar, rootstock and soil-induced vigor should also be considered when determining in-row tree spacing, particularly for high density plantings. Trees at high-fertility sites exhibiting greater vigor should be planted further apart (~4ft) as opposed to less vigorous trees on poor soils which can be planted closer together (~3ft) (Hoying, et al.).