A framework for evaluating the topic
Planning note: A centre PPFD value does not show uniformity; design is verified with a multi-point crop-plane map and operating scenario.
Relate fixture photon efficacy, distribution, mounting height, dimming and measurement grid to uniformity at crop level. This resource provides general technical information. Final capacity, equipment and implementation choices require engineering calculations based on site and project data.
PPF describes total fixture output and photon efficacy output per unit of electricity; neither alone describes distribution at crop level.
Mounting height and spacing are assessed with optics on a PPFD grid, reporting the minimum and variability as well as the mean.
Catalogue data will not represent the site unless edge rows, structural shadows, dimming state and daylight are included in the measurement plan.
Topics covered in technical assessment
PPF and photon efficacy
PPF describes total fixture output and photon efficacy output per unit of electricity; neither alone describes distribution at crop level.
Distribution curve and optics
Mounting height and spacing are assessed with optics on a PPFD grid, reporting the minimum and variability as well as the mean.
Mounting height and fixture spacing
Catalogue data will not represent the site unless edge rows, structural shadows, dimming state and daylight are included in the measurement plan.
Edge losses and row geometry
PPF describes total fixture output and photon efficacy output per unit of electricity; neither alone describes distribution at crop level.
Measurement grid and sensor level
Mounting height and spacing are assessed with optics on a PPFD grid, reporting the minimum and variability as well as the mean.
Mean, minimum and variability
Catalogue data will not represent the site unless edge rows, structural shadows, dimming state and daylight are included in the measurement plan.
Dimming and daylight integration
PPF describes total fixture output and photon efficacy output per unit of electricity; neither alone describes distribution at crop level.
Driver temperature, cleaning and maintenance
Mounting height and spacing are assessed with optics on a PPFD grid, reporting the minimum and variability as well as the mean.
Planning and comparison logic
Relate fixture photon efficacy, distribution, mounting height, dimming and measurement grid to uniformity at crop level.
| Input to verify | Effect on the decision | How to verify it |
|---|---|---|
| PPF and photon efficacy | PPF describes total fixture output and photon efficacy output per unit of electricity; neither alone describes distribution at crop level. | Edge losses and row geometry |
| Distribution curve and optics | Mounting height and spacing are assessed with optics on a PPFD grid, reporting the minimum and variability as well as the mean. | Measurement grid and sensor level |
| Mounting height and fixture spacing | Catalogue data will not represent the site unless edge rows, structural shadows, dimming state and daylight are included in the measurement plan. | Mean, minimum and variability |
Common mistakes
Mean, minimum and variability
Mounting height and spacing are assessed with optics on a PPFD grid, reporting the minimum and variability as well as the mean.
Dimming and daylight integration
Catalogue data will not represent the site unless edge rows, structural shadows, dimming state and daylight are included in the measurement plan.
Driver temperature, cleaning and maintenance
PPF describes total fixture output and photon efficacy output per unit of electricity; neither alone describes distribution at crop level.
Why does this matter in your project?
Planning note: A centre PPFD value does not show uniformity; design is verified with a multi-point crop-plane map and operating scenario.
This resource provides general technical information. Final capacity, equipment and implementation choices require engineering calculations based on site and project data.
Explore the related systemTechnical references
Frequently Asked Questions: Grow-Light LED Selection and Light Uniformity
How should ppf and photon efficacy be assessed?
PPF describes total fixture output and photon efficacy output per unit of electricity; neither alone describes distribution at crop level.
How should distribution curve and optics be assessed?
Mounting height and spacing are assessed with optics on a PPFD grid, reporting the minimum and variability as well as the mean.
How should mounting height and fixture spacing be assessed?
Catalogue data will not represent the site unless edge rows, structural shadows, dimming state and daylight are included in the measurement plan.
How should edge losses and row geometry be assessed?
PPF describes total fixture output and photon efficacy output per unit of electricity; neither alone describes distribution at crop level.
How should measurement grid and sensor level be assessed?
Mounting height and spacing are assessed with optics on a PPFD grid, reporting the minimum and variability as well as the mean.