How high should I hang my grow light?
Mounting-height comparison using measured light output
See which hanging height fits your plants best.
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How to use this estimate
Choose the plant type, drag the slider to preview hang height, then get a starting tip from the sample chart. Open Advanced only if you want to paste height → brightness lines from your light’s product chart.
Common mistakes
- Skipping plant type so the tool cannot tell low-light from high-light needs
- Entering only one distance when the product chart shows several
- Mixing fixture-level ratings with leaf-height readings
- Ignoring coverage when chasing maximum intensity
Assumptions at a glance
Last reviewed with the calculator formula set on 2026-07-23. Estimates stay range-based on purpose.
Key sources and methodology details
- Manufacturer or meter PPFD map preferred over inverse-square — Horticultural lighting practice / UNH Extension. Reviewed 2026-07-26. https://extension.unh.edu/resource/growing-seedlings-under-lights-fact-sheet
- Daily Light Integral from PPFD and photoperiod — University of New Hampshire Extension. Reviewed 2026-07-26. https://extension.unh.edu/resource/supplemental-lighting-run-time-worksheet
- Indoor plant light category DLI planning ranges — University of New Hampshire Extension (synthesized planning bands). Reviewed 2026-07-26. https://extension.unh.edu/blog/2021/02/optimizing-plant-growth-indoor-lighting-qa
Full portfolio methodology: Methodology
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EnergyWhat will my grow light cost?See daily and monthly operating cost for your fixtures and schedule.ScheduleHow long should I run my grow light?Get a practical daily runtime range for your plant type.SchedulePlan lighting for seedlings and herbsBuild a grow-light schedule aimed at seedlings or culinary herbs.
