Technical Articles & Guides

XineLam · Zhongshan City Ruixian Electronics Factory

Long-form, source-referenced guides on LED lighting for plants. Every article states its figures with the conditions they were measured under, links to the primary literature or industry standards behind each claim, and keeps product references to the short sections where they are genuinely relevant. New guides are added regularly.

Grow light technology

• Are LED Grow Lights Waterproof? IP Ratings Explained

  What IP65, IP66, IP67 and IP68 mean under IEC 60529, the water tests behind each level, and which rating a greenhouse, propagation room or grow tent actually needs.

  Published 21 September 2026

• Signs of Too Much Light on Plants: Bleaching and Light Burn

  How to recognise light burn, bleaching and photoinhibition under LED grow lights, separate them from nutrient problems, and correct the cause with measured PPFD and DLI.

  Published 21 September 2026

• How Much Does It Cost to Run an LED Grow Light?

  Convert watts and hours into kilowatt-hours, apply your own electricity rate, and see what 60-600 W fixtures cost to run, with tariff and photoperiod comparison tables.

  Published 15 September 2026

• Can I Use a Regular LED Bulb as a Grow Light?

  What an ordinary household LED bulb can and cannot do for plants, how PAR, PPF and PPFD differ from lumens, and when a dedicated fixture pays off.

  Published 15 September 2026

• Do LED Grow Lights Produce Heat? Radiant and Convective Heat Explained

  Every watt of fixture input leaves as photons or as heat. Sets out where the energy goes, why the radiant-to-convective split changes canopy temperature, why a lighting upgrade shifts the heating and cooling balance, and how to convert fixture wattage into a cooling load.

  Published 12 September 2026

• Do Plants Need UV Light? UV-A, UV-B and the UVR8 Response Explained

  Ultraviolet sits outside the photosynthetic waveband and supplies no energy, yet plants read it as a signal through the UVR8 receptor. Separates the UV-A, UV-B and UV-C bands, walks through the signalling cascade, and reports measured dose-response results from controlled lettuce trials.

  Published 12 September 2026

• How to Size an LED Grow Light: PPFD, DLI and Efficacy Explained

  A four-step sizing method that uses only plant-relevant units — PPF, PPFD, DLI and photosynthetic photon efficacy. Includes crop DLI reference values, a PPFD-to-DLI conversion table, and a running-cost comparison across fixture efficacies.

  Published 11 September 2026

• Does Far-Red Light Increase Plant Growth? R:FR Ratio and the Emerson Effect

  Far-red sits outside the PAR waveband, so it is missing from most fixtures' headline output figure, yet plants read it. This guide separates the phytochrome signalling effect from the photochemical Emerson enhancement effect, and sets out the measured dose ranges and trade-offs.

  Published 11 September 2026

• How Long Do LED Grow Lights Last? L70, LM-80 and TM-21 Explained

  LED luminaires fade rather than fail. How L70, LM-80 and TM-21 define rated life, why the standards' 6X rule caps long projections, what the horticultural industry actually reports, and how to plan replacement around PPFD depreciation rather than a marketing number.

  Published 11 September 2026

• How Many Hours Should LED Grow Lights Be On? A Photoperiod Guide

  How day length differs from daily light integral, the hours per day advised for indoor growing, and how schedules change by growth stage.

  Published 16 September 2026

• LED Grow Light Wattage: Actual Power Draw vs Equivalent Rating

  What an equivalent wattage rating really means, how to find a fixture's rated input power, and which metrics actually predict plant light.

  Published 16 September 2026

• How to Measure PPFD Without a Quantum Sensor: Six Practical Options

  Six ways to obtain a PPFD figure without owning a quantum sensor — lux conversion factors, phone apps and fixture maps — with the error each one carries and a PPFD-to-DLI conversion table.

  Published 17 September 2026

• Constant Current vs Constant Voltage LED Drivers: How to Choose

  What each driver type regulates, how to check an output window against an LED string, which dimming interfaces apply, and the standards behind the label.

  Published 17 September 2026

• What Color Light Do Plants Need? Red, Blue and White LED Spectra Compared

  How blue, red and far-red wavelengths act on plants, what controlled studies measured at each wavelength, and how to read the spectrum figure on a fixture.

  Published 18 September 2026

• Greenhouse Supplemental Lighting with LEDs: When It Pays Off

  The daily light integral thresholds below which greenhouse supplemental lighting clearly pays, the seasonal window, and a dimension comparison of LEDs against discharge lamps.

  Published 18 September 2026

• Why Do LED Grow Lights Have Fans? Active vs Passive Cooling Explained

  Where the heat inside an LED grow light comes from, how active and passive cooling differ, and how to tell when a fixture is running too hot.

  Published 19 September 2026

• Do LED Grow Lights Work With Smart Plugs and Timers?

  What happens when an LED driver is switched by a timer or smart plug, why inrush current matters, and how to compare the control methods.

  Published 19 September 2026

• How Much Light Do Microgreens Need? PPFD, DLI and Photoperiod

  Microgreens light requirements by stage: published PPFD and DLI ranges, a PPFD-to-DLI conversion table, the dark period after sowing, and where trays are most often under-lit.

  Published 22 September 2026

• How Even Is Your Grow Light? Measuring PPFD Uniformity and Fixing Hot Spots

  Why an average PPFD figure hides hot spots and dim edges: how CV and min/max ratios describe spread, how many points to measure, and which fixture changes actually flatten a canopy.

  Published 22 September 2026

• How to Compare LED Grow Light Efficacy: µmol/J Explained

  What photosynthetic photon efficacy measures, why the fixture figure is lower than the LED datasheet, and the published reference values worth checking.

  Published 23 September 2026

• Grow Light Uniformity: How to Read PPFD Distribution and Edge Drop

  How to measure PPFD across a canopy with a grid, why the minimum-to-average ratio misleads, and how mounting height drives edge drop.

  Published 23 September 2026

• Does Adding CO2 Let Plants Use More Light? The Light Saturation Point Explained

  How the light saturation point works, why sealed rooms drift below ambient CO2, and the enrichment levels and timing that are actually reported.

  Published 27 September 2026

• Which Light Is Best for Seedlings and Cuttings? A Propagation Lighting Guide

  The five criteria that matter when lighting a propagation bench, how fluorescent, MH, HPS and LED options compare, and how to set photoperiod and height.

  Published 27 September 2026

• Why Are My Seedlings Leggy? LED Grow Light Distance and Intensity Fixes

  How to diagnose seedling stretch with a daily light integral target, the PPFD-and-hours arithmetic behind it, and the day-night temperature gap that also stretches plants.

  Published 28 September 2026

• PPFD vs Lux: Which Should You Measure for Grow Lights?

  Why lux is weighted to human vision and PPFD counts photons, the published conversion factors that differ by lamp type, and what to measure instead.

  Published 28 September 2026

• LED Grow Light Dimming: How to Use a Dimmer at Each Growth Stage

  The four dimming interfaces found on horticultural LED drivers, why intensity should follow the growth stage, and how to convert a target DLI into a dim setting.

  Published 29 September 2026

• Reflective Walls in a Grow Room: How Much Extra PPFD Do They Add?

  Specular versus diffuse reflection, a practical material comparison, and measured greenhouse results showing how much the surface choice matters.

  Published 29 September 2026

• How to Light a Vertical Farm: Multilayer Rack Lighting Design

  The design order for rack lighting: set a DLI target, convert it to PPFD and photoperiod, fix layer height, then check uniformity and heat load.

  Published 30 September 2026

• What Light Do Tissue Culture Plants Need? PPFD, Spectrum and Photoperiod

  What in vitro cultures actually receive: the working PPFD range, how blue and red ratios affect proliferation, and why 16 hours is the default photoperiod.

  Published 30 September 2026

About the publisher

Zhongshan City Ruixian Electronics Factory (XineLam) has 17 years of experience designing and manufacturing LED lighting, and holds 300+ patents in China and internationally. The articles on this page are written as technical reference material for growers, specifiers and researchers; they are not product brochures.