Disclaimer
PlantLightIndex provides horticultural information, measurement tools, evidence summaries, datasets, and practical light references. The information is educational and does not guarantee a particular plant, fixture, or growing result.
Horticultural information is not a guarantee
Plant response depends on more than light. Species or cultivar identity, acclimation, temperature, humidity, watering, nutrition, root health, leaf age, pests, growing medium, and other environmental conditions can change how a plant responds to the same measured PPFD or DLI.
A practical indoor PPFD reference is therefore a decision aid, not a promise of ideal growth. It is also not automatically a survival threshold, damage threshold, photosynthetic saturation point, or universal optimum.
Measurements, calculations, and estimates
PPFD and DLI calculations are only as useful as the inputs and evidence behind them. User-entered PPFD readings can vary with sensor quality, calibration, angle, measurement position, spectral response, and canopy geometry. Window-light estimates are broad approximations because natural light changes with latitude, season, weather, glass, curtains, nearby buildings, trees, distance, and time of day.
Grow-light distance estimates depend on the stored measurement points for the exact fixture and setup. PlantLightIndex does not treat wattage or PPF alone as a substitute for leaf-level PPFD. Interpolated values remain estimates, and the site does not intentionally extrapolate beyond the measured span used by a supported fixture curve.
Evidence and source limitations
PlantLightIndex distinguishes exact species or cultivar evidence from parent-species, genus-level, experimental, greenhouse, interiorscape, manufacturer, and other contexts. Some records have stronger quantitative evidence than others. A confidence label describes the strength and relevance of the available record; it does not eliminate uncertainty.
Scientific taxonomy, product specifications, manufacturer pages, and research findings can change. Sources may be corrected, moved, superseded, or interpreted differently as stronger evidence becomes available. See the methodology and source library for the site's evidence approach.
Grow-light products and electrical safety
Product specifications and fixture measurements are provided for informational comparison. Always follow the manufacturer's installation, mounting, electrical, clearance, heat-management, moisture, timer, and operating instructions for the exact product you own. Do not use a PlantLightIndex distance estimate as a substitute for manufacturer safety requirements or applicable electrical rules.
Product names, specifications, availability, revisions, and performance claims can change without notice. A fixture page may refer to a specific model or revision and should not be assumed to describe every product sold under a similar name.
Affiliate disclosure
PlantLightIndex may use affiliate links to relevant products and services. If you click an affiliate link and make a qualifying purchase, PlantLightIndex may earn a commission at no additional cost to you.
Affiliate relationships do not determine plant-light recommendations, PPFD evidence, fixture measurement status, confidence labels, or calculator results. Product inclusion and evidence scoring are intended to remain separate from referral compensation.
No endorsement or warranty
A link to a manufacturer, retailer, paper, institution, or other external website does not mean PlantLightIndex guarantees or endorses every statement, product, policy, or service on that site. External websites are controlled by their respective owners.
PlantLightIndex makes reasonable efforts to present useful and evidence-aware information, but the website and its content are provided without a guarantee that every value is complete, current, error-free, suitable for a particular setup, or available in every region.
Use your own observation and measurement
PlantLightIndex is most useful when its references are combined with direct observation. Measure PPFD at leaf level when possible, record light duration when DLI matters, watch the plant's response over time, and make gradual changes when moving a plant into substantially brighter conditions.
If you find a source conflict, taxonomy issue, calculator problem, or fixture measurement that may improve the database, use the contact form and include enough information to evaluate the correction.