Loading…
From an empty room to a defensible photometric layout: crop-stage targets, DLC fixtures, an auto-generated array, and a point-by-point PPFD heatmap you can hand to an electrician.
900 µmol/m²/s is a common target for the bulking weeks of cannabis flower: high enough to drive yield in a CO₂-supplemented room, low enough to stay inside the 800–1,200 µmol/m²/s band that VibeLux's cannabis crop profile carries for mid-flower. This guide walks the actual designer workflow — each step below maps to a tool that exists in the product today.
Open the Design Studio and create your room — length, width, and ceiling height, plus the canopy/working plane the calculations should target. Get the mounting height right up front: PPFD falls off with distance, so a layout tuned at 6 ft of clearance will read very differently at 3 ft. On the Free plan the designer supports one room with up to 10 fixtures — enough for a small flower room or a first pass at a larger one.
Use the crop target picker to select Cannabis, then the flowering stage you're designing for. VibeLux's cannabis profile carries research-sourced, stage-specific targets: mid-flower (bulk) runs 800–1,200 µmol/m²/s with an optimum around 950, on a strict 12-hour photoperiod. A 900 PPFD design sits comfortably inside that band and works out to a DLI of about 39 mol/m²/day at 12 hours — the picker applies the PPFD, DLI, photoperiod, and climate targets to your design state so every later readout is judged against them.
Open the fixture library and browse the bundled DLC horticultural catalog (2,400+ entries). Leave the "Active QPL only" toggle on — it's on by default and hides delisted models that typically no longer qualify for utility rebates. Sort by efficacy (PPE, µmol/J) to shortlist high-efficiency fixtures, and check PPF output: at 900 PPFD over a dense canopy you'll generally want high-output top-lights rather than many small boards.
Instead of dropping fixtures one by one, use the PPFD target array tool: give it your target (900 µmol/m²/s) and chosen fixture, and it proposes a rows-by-columns grid sized to your room, with a live preview of the predicted average PPFD before you apply it. If the layout it needs exceeds your plan's fixture cap, the tool tells you so explicitly rather than silently truncating the design.
The PPFD map is computed point-by-point from each fixture's IES LM-63 photometry with candela interpolation — not a generic beam-angle approximation. Look at three things: the average PPFD against your 900 target, the min/avg uniformity ratio (many cannabis growers aim for roughly 0.7 or better so edge plants aren't starved), and the hot spots — a 1,200+ µmol/m²/s zone under every fixture with dark aisles between them means you should raise the mounting height or tighten spacing, even if the average looks right.
The design readouts include the connected load and lighting power density (LPD) for the room — the numbers your electrician and your utility rebate application will ask for. When the layout is dialed in, export the photometric report: PDF reports are available on paid plans (Solo and up), DXF export starts at Starter, and IES export at Teams. The Free plan exports the design as JSON.
The photometric math is identical on every plan — the tiers change room and fixture capacity and export formats, not calculation quality.