Does led cause slow flowering


This my second grow first one was full sun 8am till 8pm now I have to strictly stay indoor due to new neighbors so now they are under led from 8pm till 8am they are currently in the start of week 2 and just starting to see change these led’s are suppose to be 300 watts which maybe only 160 watts but I have 2 led’s so I Guess is close to really being 300 watts but progress seems to be slow compared to when I was getting 12 hrs of sun…will cause small yield and small buds or should I add more led don’t want to go with hps or hid and have to deal with heat issue’s already dealing with that now in tent



If you don’t have a watt meter to measure watt at the light’s plug, and you can’t get specs from the manufacturer, then assume 50% or less. So only 150 watts or less.

The LED itself did not necessarily cause any of delays in flowering. In fact many people report the opposite with LED, quicker signs of flowering.

With LEDs, you need about 35 actual watts per square foot. This formula should help you figure out if you have enough light.



Ok thks Mac, I will chk spec’s and figure it out and report back think I’m just being impatient


There is some evidence redder light may quicken flowering, and bluer light may delay it, but your light in these photos does look “red light dominant” in its shade of purple, so again, if anything, this type or spectrum of LED would probably contribute to a little quicker flowering.

Happy flowering,



Led dont cause slow flowering normally its just seeds but its may be a number of factors from your medium to your waters PH humidity etc.


I agree, but I think it’s specifically far reds to infrared wavelengths.


This is true, far red and near infrared can accelerate the breakdown of PFR to PR, which this process naturally occurs overnight with the absence of light.

It is the long night in the fall winter that allows enough of the PFR to break down into PR, resulting in enough PR to signal flowering.

Happy growing,