Will this light cover my plant shelf?
Plant-shelf coverage planner
See how many lights you need and how to space them.
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How to use this estimate
Pick a shelf preset, add light bars, and watch coverage by shelf. Dim edges are normal — plan fixtures for the useful center first.
Common mistakes
- Covering only the center and leaving edges chronically dim
- Mounting fixtures too high without checking intensity drop
- Assuming one bar always covers a full 48-inch shelf
- Skipping a leaf-height check after rearranging
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
- Shelf fixture count and spacing heuristic — Plant Light Planner geometry heuristic. Reviewed 2026-07-26. https://extension.unh.edu/resource/growing-seedlings-under-lights-fact-sheet
- Bar-light edge falloff on deep shelves — Plant Light Planner coverage heuristic. 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
