TryBuildCalcTriangular Spacing Calculator (Staggered / Hexagonal Packing)
Size a triangular-spaced garden bed instantly.
🕒 Last updated: September 22, 2026
Inputs
ℹ️For an irregular bed, measure its overall rectangular footprint, or switch to By Total Area above.
Plant Type & Spacing
ℹ️A commonly-cited representative recommended spacing for this plant type. Select Custom Spacing to enter your specific variety/cultivar's own recommended distance instead.
Compact/dwarf bedding varieties can go as close as 6 in; check your specific variety's plant tag for its exact recommended spacing.
Square/Grid plants in straight rows and columns across the whole bed. Triangular/Staggered offsets alternating rows, commonly fitting more plants in the same area at the same spacing by eliminating wasted corner gaps. Single Row (Hedge / Border) plants along the bed's length only — for a hedge or border, not a multi-row bed — and ignores bed width entirely. This is your own explicit choice, independent of which plant type is selected above.
Cost
Plants Needed
228
plants total
Rows
13
~18 plants per row (varies by row)
Bed Area & Layout
Bed area: 150 sq ft (13.9355 m²)
Layout pattern: Triangular / Staggered
Spacing used: 10 in (25.4 cm)
Area per plant: ~0.66 sq ft
Plant Type & Count
Plant type: Bedding Flowers (Marigolds, Petunias, Annuals)
Rows (staggered): 13
Total plants needed: 228
Assumptions Used
The spacing distance used (Compact/dwarf bedding varieties can go as close as 6 in; check your specific variety's plant tag for its exact recommended spacing.) is a commonly cited reference figure for Bedding Flowers (Marigolds, Petunias, Annuals) — a specific variety/cultivar's own plant-tag or seed-packet spacing should be used when available, via the Custom Spacing option above. Triangular/staggered spacing generally fits more plants than square spacing at the same distance, but the exact gain depends on the bed's real dimensions relative to the spacing (edge effects can reduce or, for a very small bed, reverse the usual advantage). This calculator estimates plant count and layout only— it does not check your specific site's sun exposure, soil, or hardiness zone suitability for the selected plant type.
Diagram simplified for clarity (not to scale) — bed shown schematically, plant positions shown illustratively.
Looking for the verification checklist, reference tables, tips, or common mistakes?See the complete Plant Spacing Calculator.
Triangular / staggered plant count
Triangular (hexagonal-packing) spacing offsets every other row by half the spacing distance and moves the rows themselves closer together — spacing x sin(60°), about 0.866x the full spacing — which commonly fits roughly 15% more plants than a square grid in a bed with several rows, for the same on-center spacing.
This page defaults to a 15 ft x 10 ft bed planted with bedding flowers at their typical 10 in spacing in a triangular layout — edit the inputs above to compare it against a Square/Grid layout for the same bed.
Plant Spacing Calculator Formula: How Is It Determined?
Bed area (or length x width) combines with a spacing distance (set by plant type or a custom override) and a layout pattern into a real row-by-row plant count — never a rough area-divided-by-spacing estimate.
Step 1 — Bed Area & Dimensions
By Dimensions: Area = Length x Width
By Total Area: Area = entered value; Length = Width = sqrt(Area) (equivalent square)
Either enter a rectangular bed's length and width, or enter its total area directly — an area entered directly is treated as an equivalent square purely to determine rows and plants-per-row, since that breakdown genuinely needs two dimensions.
Step 2 — Spacing Distance
Spacing = selected plant type's typical distance, or your Custom Spacing override
Each plant type preset carries its own commonly-recommended on-center spacing distance — or enter your specific variety's own recommended distance directly with the Custom Spacing option.
Step 3a — Square / Grid Plant Count
Plants per Row = floor(Length / In-Row Spacing)
Rows = floor(Width / Row Spacing)
Total Plants = Plants per Row x Rows
Each plant is set back half a spacing from the bed's edges — the same convention university-extension planning guidance uses (a bed's area divided by spacing², e.g. Iowa State/Alabama Cooperative Extension's own 100 sq ft ÷ 2 ft² = 25-plant example), not a plant placed literally on the border. Row Spacing defaults to the same distance as In-Row Spacing (symmetric spacing, the normal case) unless you turn on "Use Separate Row Spacing?" for an asymmetric block-row crop like corn.
Step 3b — Triangular / Staggered Plant Count
Row Spacing = Spacing x sin(60°) ≈ Spacing x 0.866
Rows = floor(Width / Row Spacing)
Each row's count computed individually (alternating rows offset by half the spacing)
Triangular spacing packs rows closer together (≈86.6% of the full spacing apart) since alternating rows are offset, which commonly fits roughly 15% more plants in a bed with several rows for the same spacing distance — computed row-by-row here so the count is exact for your real bed, not a flat +15% assumption (see the Reference Tables section below for the full derivation and its real-world limits). Uses the same half-spacing-margin edge convention as Square/Grid above.
Step 3c — Single Row (Hedge / Border) Plant Count
Plants in Row = floor(Length / Spacing) + 1
Total Plants = Plants in Row
A hedge or border genuinely wants a plant at EACH end for continuous coverage corner to corner — a different, edge-inclusive convention from the interior bed planting above, not an inconsistency. Only the bed's length is used; width is ignored entirely, since a hedge is a line, not a 2D bed.
Worked Example
This example walks through your current inputs above, using the same steps as the Formula section.
Input Values Used
| Input | Value | Why it is used |
|---|---|---|
| Bed Area | 150 sq ft (13.9355 m²) | Sets the grid dimensions |
| Plant Type | Bedding Flowers (Marigolds, Petunias, Annuals) | Sets the spacing distance |
| Spacing | 10 in (25.4 cm) | Sets the grid spacing divisor |
| Layout Pattern | Triangular / Staggered | Sets the row-count formula used |
Step 1 & 2 — Dimensions & Spacing
| Calculation | Result |
|---|---|
| Bed Dimensions (real or equivalent square) | 15 ft x 10 ft |
| Spacing Distance | 10 in (25.4 cm) |
Step 3 — Plant Count
| Calculation | Result |
|---|---|
| Row Spacing = 0.833 ft x sin(60°) | 0.722 ft |
| Rows = floor(10 / 0.722) | 13 rows |
| Total Plants (summed row by row) | 228 plants |
Figures above are rounded for display; the plant/pack count is always calculated from full, unrounded values, so it can occasionally look off by one if you redo the division yourself using the rounded figures shown.
Therefore, a 150 sq ft bed planted with Bedding Flowers at 10 in spacing in a Triangular / Staggered layout needs approximately 228 plants.
Related Calculators
Disclaimer: This calculator provides approximate results for planning and estimation purposes only. Actual requirements may vary based on site conditions, materials, workmanship, and local building regulations. Always consult a qualified engineer, architect, or construction professional before making final decisions.