I have a guestion about lights


Question from a fellow grower:

My question is: Is there any advantage or disadvantage to lighting plants from underneath (underlighting)?


I’m definitely not an expert, but I’d say you can benefit from it than not doing it at all… I don’t use underlights. i just use an led ontop and side lighting, and rotate my plant 90 degrees atleast once a day so all sides of the plant get equal lighting


You can do SIDE lighting but they do not take in light underneath the leaves,just on top


Plant leaves process very little light, if any, on the bottom of leaves, only the top, so it wouldn’t help much. Photosynthesis happens on the top side of leaves. The bottom side is where the stomata are located. Pores that allow gasses in and out of the plant. Light/heat can cause those to close.

Way better off using that light above or maybe the sides, but not underneath.


@Matthew420 is absoletly wright, the stomata are closing by light and warmth. So it’s not a good idea.


And if light is too strong, it may cause light burn to the softier tissus beneath and cause irréparable damage to the stomata and disrupt the processus of breathing of the plant and cause suffocation and death.


I thought temp and humidity were the things that affect stomata functions?


In fact it’s light, humidity, co2, o2 and temperature differencies that induce the stomata to opening and closing. And i’ve make an honnest mistake, the stomata open about 30 minutes after been expose to light and closing about 30 minutes after dark.

But too much light cause dryness and the plant will react in closing her stomata too conserve humidity.

Sorry for the lack of information :innocent: