Bays, not posts
A row of 350 feet at 24 foot post spacing does not hold 14.58 posts. It holds a whole number of bays — 15 of them, at an actual spacing of 23.33 feet — with an end assembly at each end and 14 line posts between. Counting bays and subtracting one is the reliable way round; counting posts directly is where the off-by-one lives.
Dividing the run evenly across the bays also avoids the short bay at one end that you get from marking out at exactly 24 feet and stopping when you run out of row. A 12 foot last bay looks like a mistake because it is one, and it is the bay that fails first when the crop comes on.
The tie-off allowance is not optional
Wire has to wrap, go through a tensioner and leave a tail. Three feet at each end is modest. On 16 rows with 3 wires that is 288 feet of wire that does no work at all — enough on its own to change how many coils you order. The default block here comes to 17,088 feet, which is five 4,000 foot coils and a bit, not four.
| Block | Wires | Wire at 3 ft tie-off | 4,000 ft coils |
|---|---|---|---|
| 16 rows x 350 ft | 2 | 11,392 ft | 3 |
| 16 rows x 350 ft | 3 | 17,088 ft | 5 |
| 40 rows x 500 ft | 3 | 60,720 ft | 16 |
End assemblies carry the whole row
Every bit of tension in every wire on a row ends up at its two end assemblies, and that is where trellises fail. The line posts hold the wire up; the ends hold it back. That is why an end assembly is a different item from a line post in the materials list, and usually a much more expensive one — a heavier post, plus either an earth anchor or a second post braced to it.
What size those need to be is genuinely an engineering question. It depends on the number of wires, the tension in each, the crop weight, the soil the anchor is going into and the wind the site gets. Nothing on this page evaluates any of that, and a materials count that comes out neat is not evidence that the design works. Post and wire ratings come from the supplier; the anchor and brace design for your soil comes from someone qualified to do it.
Getting the row count and length
If you are starting from a block rather than from a row count, the orchard row layout calculator turns block dimensions, row spacing and headlands into the row count and row length this page wants. For the plants that go on the trellis and what they eventually produce, see the fruit harvest bin calculator; for water down the row, the drip emitter calculator handles zone flow and run time. Perimeter fencing against deer is a different takeoff, covered by the fence post calculator and the livestock fence calculator.
Questions people ask
How far apart should the line posts go?
The honest answer is that it depends on the wire, the number of wires, the crop load, the soil and the wind, and that a page which gives you a single number is guessing on your behalf. Trellis suppliers publish spacing guidance for their post and wire combinations, and it is specific to the product. What this calculator does is take your spacing and turn it into counts that are right, including dividing the run evenly so there is no stub bay at the end.
Why is the actual spacing different from what I entered?
Because a row rarely divides evenly. Entering 24 feet on a 350 foot row gives 14.58 bays, which is not a thing, so the calculator rounds up to 15 bays and divides the row evenly across them — 23.33 feet. That is tighter than you asked for rather than looser, which is the safe direction to round, and it avoids the short final bay you get from marking out at a fixed distance and stopping at the end.
Do I need an anchor at every end?
Every end assembly has to resist the pull of every wire on that row, and there are two ends per row, so whatever your design is, it happens twice. Whether that is an earth anchor, a braced pair of posts, or something else is a design choice with soil and load implications, which is why it is a selection here rather than an assumption. Getting it wrong is the classic trellis failure: the ends lean in, the wires go slack, and the whole row has to be re-tensioned or rebuilt with fruit on it.
How much wire is wasted?
The tie-off allowance is the visible part, and at three feet per end on a three wire block it comes to about 1.7 percent of the total on a 350 foot row. The invisible part is what is left on the coil at the end, which is why the coil count in the calculator rounds up and shows the remainder. If the remainder is large, ordering one longer coil rather than several short ones usually reduces it.
Can I use this for an orchard rather than a vineyard?
Yes. High-density orchards on dwarfing rootstock are trellised much like a vineyard, with line posts, tiers of wire and end assemblies, and the counting is identical. The number of wires and the post spacing will differ, and the load a trellis carrying fruit trees sees is not the same as one carrying vines — which is again a reason to take the structural side to the supplier and to an engineer rather than to any calculator.