Bests & Worsts Reviews from Amazon

It's brighter than I'd expect a USB powered lamp to be, but weaker then I'd expect a grow light to be. At about 12" away from the light bar, it's around 800-900 lux at the brightest setting, according to my phone. That's pretty dim at such a short distance. For reference, • direct sunlight ~ 32,000 - 100,000 lux • midday shade on clear day ~20,000 • overcast 1,000 - 2000 lux (Source: Wikipedia) Only the lowest light loving plants will thrive in this level. This is a convenient grow light, I am very impressed by the usability and ease of set up, but don't expect super happy plants or herbs that really produce. That being said, at my window that gets 300 lux at best, it has helped the few plants that it covers.