Library · Structures, greenhouse & energy

Coverage Layout Designer.

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What this is
Designer
Domain
Structures, greenhouse & energy
Cost
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Coverage Layout Designer

Plan your grow-room fixture layout. Visualize coverage, overlap, and PPFD uniformity.

Room and fixture parameters

From fixture spec sheet
Drives the uniformity model
Fixtures recommended — — grid
Total system PPF —μmol/s
Average PPFD at canopy —μmol/m²/s Across full room
DLI at 12h —mol/m²/d
DLI at 18h —mol/m²/d
Coverage utilization —% Effective coverage / room

Layout visualization

Top-down view of your room with fixture coverage areas (lighter rectangles).

PPFD uniformity (canopy heatmap)

Modeled canopy-level PPFD across the room — an extended-source cosine estimate, not a measurement. Brighter = more light; dim corners and seams are where uniformity falls off. Per ASABE S640, uniformity = minimum ÷ average, measured over the canopy zone (inset from the walls, as growers actually plant). Reflective walls (not modeled here) lift the edges further.

Min PPFD—μmol/m²/s
Avg PPFD (modeled)—μmol/m²/s
Max PPFD—μmol/m²/s
Uniformity (min/avg)—%—
dimbright

How fixture coverage works

Fixture coverage is the rated area at the fixture's design hang distance (typically 18-24" for indoor LED, often closer or farther for HID/CMH). At that distance, average PPFD across the rated area is approximately uniform — but uniformity drops at the edges, and the corner-to-center variance is significant.

0% overlap means fixtures are placed at exactly their rated coverage area edge-to-edge. Center-of-canopy PPFD hits the rated number, but the seams between fixtures get less light.

10-20% overlap places fixtures slightly closer; the seams overlap and uniformity improves. Total system PPF goes up (more fixtures), so PPFD increases as well.

30%+ overlap is for tunnel-grown / dense-canopy operations where uniformity matters more than energy efficiency. Common in commercial cannabis operations targeting maximum yield.

When to choose more fixtures

  • High-DLI crops (cannabis flower 50+ mol/m²/d): need higher PPFD; more fixtures or higher overlap
  • SCROG / SOG: dense uniform canopy; high overlap improves yield distribution
  • Larger plants: side-light penetration matters; multiple fixtures vs single big one
  • Tall canopies: PPFD drops at canopy depth; better fixture distribution helps lower buds

When fewer fixtures is fine

  • Lettuce / leafy greens: 12-17 DLI is plenty; one fixture per area is often sufficient
  • Microgreens: short cycle, low DLI, minimal stretch tolerance — uniform single fixture works
  • Mother plants / propagation: low DLI; one fixture for many plants
  • Mushroom rooms: indirect dim light; usually 1 fixture for the whole room

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Free under CC BY 4.0. Cite as "OAT Coverage Layout Designer (openagriculturetechnology.com)".