Trellis Spacing Calculator
Calculate post spacing, wire rows, and total materials for a garden trellis from bed length and plant type.
Returns lumber, wire length, and anchor counts.
Designing a Garden Trellis
A well-built trellis supports climbing plants while allowing good airflow, light penetration, and easy harvesting. The right spacing depends on plant type, expected weight, and how you want to train the vines.
Post Spacing by Plant Type
| Plant | Post Spacing | Wire Rows | Wire Height |
|---|---|---|---|
| Tomatoes | 120 cm (4 ft) | 2–3 | 30, 60, 90 cm |
| Cucumbers | 90 cm (3 ft) | 3–4 | 30, 60, 90, 120 cm |
| Beans (pole) | 60 cm (2 ft) | 1 top wire | 150–180 cm |
| Peas | 60 cm (2 ft) | 3–4 | 30, 60, 90, 120 cm |
| Grapes | 180–240 cm (6–8 ft) | 2–3 | 60, 90, 120 cm |
| Berries (cane) | 150 cm (5 ft) | 2–3 | 60, 90, 120 cm |
Post Depth Rule
Posts should be set at least one-third of their total length into the ground. For a 180 cm (6 ft) post, at least 60 cm (2 ft) is buried and 120 cm (4 ft) is left usable. Work backwards from the height you want: divide it by two-thirds to get the length of timber to buy. Wanting 150 cm of trellis means buying a 225 cm post, not a 150 cm one, which is the mistake that turns a tidy plan into a second trip to the yard.
End posts should go deeper still. They carry the whole of the wire tension, and a trellis that fails almost always fails by an end post leaning inward.
Wire Tension and Gauge
- Light plants (peas, light beans): 12–14 gauge galvanized wire, or nylon netting
- Medium plants (cucumbers, tomatoes): 12 gauge galvanized or heavy-duty netting
- Heavy plants (grapes, squash, melons): 9–11 gauge galvanized wire with turnbuckles for tension
Metric and Imperial Reference
| Spacing | Metric | Imperial |
|---|---|---|
| Close posts | 60 cm | 2 ft |
| Standard posts | 90–120 cm | 3–4 ft |
| Wide posts (grapes) | 180–240 cm | 6–8 ft |
Materials Formula
Number of posts = (bed length ÷ post spacing) + 1 (always one more post than gaps) Wire length per row = bed length + 10% extra for threading and securing Total wire = wire per row × number of rows
How we build and check this calculator
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