Will yellow light inhibit the growth of Cannabis?

[shag]

@DesertGrown

First of all, HPS is not yellow light

@shag

HPS tend to have too much (relative) energy in yellow to red wavelength ranges.

My statement holds true.
Check the statement again, please.
It speaks of a yellow to red ratio.

I am pretty darn sure HPS has some yellow.

@DesertGrown

they offer very little value to growing plants and are absorbed by the plant in very small quantities, like green light is.

Don’t ignore the green light

Don’t ignore the green light: exploring diverse roles in plant processes

@DesertGrown

it’s red/orange, but mostly red. That’s why it’s used for flowering.
MH is blue light and promotes growth.

Blue is not for veg and red is not for flowering - that’s flawed logic based upon common misunderstandings about sunlight.

Cannabis doesn’t use light (in terms of spectral quality) much different than other higher C3 plants.

The HPS is good in terms of photosynthesis, in fact, it’s YPF/PPF ratio is very high (which means per total light output there’s more photons that are more effective at driving photosynthesis than for example, an MH).

However, your el’ cheapo HPS lacks important wavebands for some photomorphogenesis.

For example, it’s likely there is more yellow light from your HPS than is good for the plants, as well as more far-red light than is helpful (leads to plant stretch). Around 10% blue light (as total radiant PPF) is a good minimum goal for plant growth lighting.