Technically Far Red is not infra-red.
en.m.wikipedia.org
Far-red light is a range of light at the extreme
red end of the
visible spectrum, just before
infra-red light. Usually regarded as the region between 700 and 750 nm
wavelength, it is dimly visible to human eyes. It is largely reflected or transmitted by
plants because of the
absorbance spectrum of
chlorophyll, and it is perceived by the plant
photoreceptorphytochrome. However, some organisms can use it as a source of energy in photosynthesis.
Infrared is not visible to the human eye. Far red is to most people. It’s the buffer zone between viable and non visible spectrum.
A lot is reflected by healthy green cannabis which is why a healthy dose (60 Watts in a 4x4 space in my experience is the minimum effective amount to impact the entire 4x4 space) is needed to see effects in flower. As seedlings much less is needed.
But I see a lot of manufacturers use Infrared rather than Far Red to describe their 730nm leds. Maybe there is more than one definition of infrared depending on the continent you are standing on. That’s gotta be frustrating for new growers to understand all this minutia