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XTi Science
Multiple Trials of XTi PAWS on Different Lettuce Varieties
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January 8, 2023

Multiple Trials of XTi PAWS on Different Lettuce Varieties 2018 – 2023

Internal XTi Trials

Conclusion: Exposure of multiple varieties of lettuce to XTi’s pulsed alternating wavelength system (PAWS) generally resulted in improved efficiencies (gram of edible plant/kWh), leaf counts, and edible plant weights.

Study Objective:

  • To evaluate the effect of XTi PAWS on production of multiple lettuce varieties.


  • Previous XTi pilot plant trials had shown a significant increase in plant growth under XTi lighting.
  • Lettuce trials were designed to evaluate edible plant growth and electrical efficiencies.


  • The studies were conducted at XTi’s research facility in northern Colorado.
  • 4 ft x 4 ft grow tents were utilized for different XTi lighting “recipes”, as well as control lighting.
  • T5 lights were generally used for control, but some trials included competitor LED lighting products.
  • XTi lights were generally on 18-24 hours/day. The control tents were lit for 12-18 hours/day.
  • Multiple seeds were planted in each pot and duplicate plants were pulled after germination.
  • Trials were done utilizing either drip, ebb and flow, or nutrient film technique watering systems.
  • Miracle Gro potting mix or Jiffy peat pellets were used as media, with or without additional fertilization depending on the trial protocol.


  • XTi recipes generally showed significantly higher efficiencies (gram of edible plant/kWh of power used), higher leaf counts, and higher edible plant weights than control plants.
  • Plants under XTi lighting generally showed overall faster growth than control plants.
  • Photoperiod and light intensity did vary the results, but XTi lighting consistently outperformed control plants.
  • Different XTi recipes showed varying abilities to affect plant size, phenotype, coloration, leaf length, leaf width, overall plant height, and taste.
  • Not every XTi “recipe” was successful, some “recipes” performed poorly compared to control lighting.


  • XTi lighting can significantly increase growth and edible plant material when used to grow lettuce.
  • Plants grow faster under XTi lighting than under control lighting.
  • XTi recipes can be used to maximize desirable plant qualities based on “recipe.”
  • These trials showed that “dark” periods are not necessary to successfully grow lettuce in an indoor setting.
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