Apple Tree Spacing

Apple orchards are a long-term investment, so it is essential to choose a tree spacing and a production system that will make best use of land and capital to produce fruit. Potential acre yields depend on the volume of bearing wood maintained in an orchard. Increasing the number of trees per acre is one way to increase the volume of bearing wood and thus yield. Yield can also be increased through proper pruning, training, and management. Growers must consider their ability or inability to manage a particular production system.

To determine in-row tree spacing, consider the following factors.

1. Variety
Table 1-6 lists common Pennsylvania-grown varieties and their characteristics, including vegetative vigor. (For example, Northern Spy is among the most vigorous and spur Delicious is among the least.)

2. Type of production systems
Low-trellis hedgerow
This system requires that the grower have a thorough understanding of tree growth and a large commitment of time and money. In a trellis hedgerow, trees are trained to a four-wire trellis to develop a solid hedge about 6 feet tall and 3 to 4 feet across. Branches originate from a main trunk below the wire and are trained up and across the wires. Trellising has the potential for high yields and early bearing and is a desirable system for growers limited by land or equipment. Suitable rootstocks and suggested in-row spacings are EMLA 9 (6 to 7 ft) and EMLA 26 (7 to 9 ft). M.27 (5 ft) can be used but is still experimental.

Slender spindle, hoop skirt, spindle bush
These systems also require a thorough understanding of tree growth. They differ from trellising in the way in which the scaffold branches are trained. In slender spindle, the scaffolds are bent and tied down to reduce shoot growth and to enhance cropping. In hoop skirt, scaffolds are trained nearly horizontal, with low limbs retained for a period of time. In spindle bush, scaffolds are developed by a combination of pruning and spreading. If posts or wires are used for support, these systems will be the most expensive to establish. Training and pruning require more effort than trellising. Yields may be slightly lower than in the trellis system, depending on the grower's commitment to pruning and training trees. These systems on EMLA 26 may not need individual tree support. Rootstocks suited for these systems and suggested in-row spacings are EMLA 27 (4 to 5 ft), EMLA 9 (5 to 7 ft), and EMLA 26 (7 to 10 ft).

Freestanding central leader tree on semidwarf rootstocks
This system uses a more vigorous rootstock to provide tree support. The tree is kept small by periodically heading back the central leader into 2-year-old wood to stiffen the tree's central axis. Trees are trained to a central leader system and pruned annually to keep them within their allotted spaces. The cost of establishing this system is relatively low because no tree supports are used and there are fewer trees per acre. Suggested rootstocks and in-row spacings are EMLA 26 (8 to 10 ft), MARK (8 to 10 ft), EMLA 7 (9 to 12 ft), M.9/MM.106 and M.9/MM.111 (10 to 13 ft), EMLA 106 (11 to 14 ft), M2 (12 to 15 ft), and EMLA 111 (15 to 18 ft).

Freestanding central leader tree on semistandard and standard rootstocks
In this system tree height is not as severely controlled. Grower knowledge, time, and expense may be the lowest of any other system. Potential yields and returns are also the lowest, especially in the early years. The age of bearing and early production will be inversely related to the ultimate size of the tree. The system still requires early pruning and spreading of branches. Suggested rootstocks and in-row spacings are EMLA 106 (16 to 20 ft), EMLA 111 (17 to 20 ft), seedling (18 to 24 ft).

3. Rootstock effect
The effect of the rootstock on ultimate size, precocity, cultural practice, and spacing is another factor to consider. Penn State has been a leader in testing and evaluating rootstocks for tree fruit. Test plantings of all the new rootstocks for apples are located at either University Park or Biglerville. The more common rootstocks are classified immediately below. Certain rootstocks in each size category may overlap into the next largest tree size owing to scion variety, production system, or soil type.

In the future there will be numerous rootstocks from which to choose. Growers are advised that many of these rootstocks have had only limited testing in Pennsylvania. We recommend proceeding with caution when trying new rootstocks, but urge you to try small test plantings with the cultivars that you grow (see Table 1-7). Brief descriptions of apple rootstocks that you may find in nurseries are provided in the Apple Rootstocks section.

4. Soil vitality
Soil type, fertility, depth, water-holding capacity, and replant conditions all affect tree spacing. Pennsylvania soils have been divided into five classes according to potential productive capacity. A listing of these classes is available at county extension offices. Soils in Classes II and III are best suited for orchards. Soils in Class I are the most fertile and can lead to overly vigorous plantings.

In-row spacings should be adjusted according to soil strength. For Class I soils the widest in-row spacing is recommended, for Class II the middle range, and for Class III the narrowest spacing. Orchard soil should be a minimum of 2 to 3 feet deep. For shallower soils, in-row spacing can be reduced. Soils with a high water-holding capacity usually encourage more vigorous growth, while droughty soils slow growth.

Old orchard sites require special attention. Continually replanting the same sites can lead to poor tree growth and production. Before being replanted, soil should lie fallow or be put into field crops for 2 or more years. Every effort should be made to replenish soil nutrients before replanting. Before removing the old trees, take a soil test and nematode analysis. After removing trees, apply the recommended amounts of lime and fertilizer. Then subsoil the site and work in the fertilizer. Organic matter additions are also suggested.

5. Cultural practices
Mulching, weed control, irrigation, and other cultural practices all affect orchard spacing. Mulching helps conserve moisture in the soil and reduces the number of competing weeds, but it can also attract meadow and pine voles. Eliminating weeds from under the tree helps reduce competition and produces a larger tree. Although Pennsylvania has a humid climate, frequent dry spells can affect tree growth and performance. Irrigation has been shown to be beneficial.

6. Equipment
The size of equipment to be used in the orchard depends largely on the between-row spacing. Maximum width between rows of trees should be the sum of in-row spacing plus 8 feet. For example, if trees are to be planted 7 feet apart in the row, then between-row spacing should be 15 feet (7 ft plus 8 ft). Adjustments downward can be made when narrower tractors and sprayers are used. When a new, more efficient planting is being established, between-row spacing should not be based solely on the width of old equipment. Until the trees fill their allotted space, larger equipment can be used. Smaller tractors can be substituted as the planting ages.

7. Between-row spacing
Research has shown that the most critical factor in determining early production and high yields in an orchard is the rapidity with which the canopy of the trees develops and fills its allotted space. In designing an orchard, growers are often more concerned about planting trees too close. Spacing trees too far apart, however, can be just as detrimental.

The overriding factor in determining optimum row spacing is to choose a spacing that will capture the most sunlight while not shading the adjacent rows. Orchards whose rows are spaced too far apart capture less than the optimum amount of sunlight. The old rule of thumb in determining row spacing is to take the in-row spacing and add 8 feet to it to equal the distance between rows. However, growers switching to small trees should avoid the mistake of keeping wide drive rows to accommodate old equipment.

As mentioned previously, in-row spacing depends upon rootstock, cultivar, training system, and other factors. Between-row spacing is determined by all of the previously mentioned factors plus the ultimate tree height. Many growers in their quest for small trees do not realize that to achieve optimal yields they must also move the rows closer together. Failure to do this will result in significantly lower yields than old standard or semidwarf plantings. The following are three methods that can be used to arrive at possible between-row spacings.

  1. (desired tree height/2 ) + in-row spacing = between-row spacing
  2. (2 x desired tree height) - 6 = between-row spacing
  3. desired tree height / 0.75 = between-row spacing


As an example, assuming you want to maintain your trees at 10 feet within the row and no more than 10 feet tall, the above formulas can be used to help estimate row spacings.

  1. 10 / 2 = 5 feet, 5 feet + 10 = 15 feet between rows
  2. (2 x 10) - 6 = 14 feet between rows
  3. 10 / 0.75 = 13 feet between rows


Therefore, the optimum distance between rows is 13 to 15 feet apart.

Finally, one way to evaluate older plantings to see if they are spaced properly is to observe them late in the afternoon on a sunny day. Looking at the base of the trees in a row, if the shadow cast from the adjacent row is covering less than 10-20 percent of the lower canopy then the trees are spaced properly. If the shadow from the adjacent tree is covering more than 20 percent of the canopy of the adjacent row, then the trees are too close together. If no shadow strikes the adjacent row, then the trees are spaced too far apart. (Portions adapted from T. Robinson, Dept. of Horticultural Sciences, NYAES, Cornell University)

Extension | Intranet | Publications |