Plant Density

Planting Density

Spacing is always a concern in new fields, especially if you are uncertain about the size of plants you will need or about the market for your crops. If you anticipate that you will sell trees to professional landscapers or that they will be used as municipal street trees, space them wider to allow for more growth before they become crowded and so that you will have better access during harvesting. Wider spacing is also encouraged if the market strategy is uncertain, because it allows more opportunity for finding a market before the trees become overgrown. A spacing method that allows the most flexibility is planting two rows 8 feet apart and a drive row of 10 to 14 feet on each side of the two rows. Repeat this pattern across the field. This spacing allows greater room for digging activities and results in less injury to trees during harvesting. Smaller flowering trees such as dogwoods and shrubbery can be spaced 6 feet apart in rows, and larger shade tree species should be spaced up to 10 feet apart in the row. In choosing planting dimensions, it is important to account for space required by fertilizing, cultivating, mowing, and spraying equipment. Each tree is considered to “own” half the space between it and the next tree or row for calculations such as the number of trees per acre. In reality, the canopies and roots may exceed half the distance by harvest time.

Examples of the number of trees required per acre with two rows then a drive row spacing pattern are as follows:

Two rows 6 feet apart, trees 4 feet apart down row, 10-foot drive rows.
4 x 8 square feet / tree= 32 square feet / tree
43,560 / 32 = 1,361 trees / acre.
Two rows 6 feet apart, trees 6 feet down row, 10-foot drive rows.
6 x 8 square feet / tree= 48 square feet/tree = 43,560 / 48 = 907 trees / acre.
Two rows 8 feet apart, trees 8 feet down row, 12-foot drive rows.
8 x 10 square feet / tree = 80 square feet / tree = 43,560 / 80 = 544 trees / acre.
Two rows 10 feet apart, trees 8 feet down row, 14 foot drive rows.
8 x 12 square feet / tree = 96 square feet / tree = 43,560 / 96 = 454 trees / acre.

Larger nurseries use main or fire break roads for field loading. Most smaller nurseries will need to load onto tractor-pulled wagons or small trucks to transport plants to the loading area. You need to plan for enough space for transport vehicles and other maintenance equipment. A rule of thumb for determining the minimum distance needed between rows is to add the width of the tractor plus the maximum width required by American Standards for Nursery Stock for that crop. For example, a tractor might be 48 inches wide. In growing a crop of five- to six-foot trees, another 48 inches are required for the plants to make grade; therefore rows must be at least 96 inches or 8 feet apart.

One method of increasing planting density is to plant some species, such as dogwoods, 3 feet apart within rows and after two years, dig and sell every other plant down the row. The following season, the remaining trees would have additional space to develop caliper and full, well-branched canopies. In theory, this method seems like a good idea. The critical issue with this plan is that you must have a sales mechanism in place for the trees that are dug after two years. If all the alternating trees are dug and sold, or possibly containerized to be sold during the current season, this plan may be feasible. However, in many cases, if the grower has no immediate market for the smaller trees or place to hold them, then the entire crop becomes over-grown and diminishes in value.

Irrigation

Planting

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