Whats PPFD?
The grow lights is special, wattage should technically not matter when deciding on an LED grow light. This is a carryover from the age of traditional HID lighting. What matters is the PPFD (photosynthetic photon flux density). PPFD is a measure of the number of photons in the 400-700nm range of the visible light spectrum that fall on a square meter of target area per second. High PPFD numbers are good, because this means your plant is 'absorbing' enough light to carryout important physiological processes. Keep in mind that there are LED lights that have high wattages, but could have low PPFD numbers.
