Not necessarily. I tape up my led indicators on a plug strip. Im aware of the study and did in anyway. 5 sec of work to eliminate a risk is not a waste. Using duct with a bend in it for the passive airflow to eliminate light is also not a waste. Just being smart. There is a difference.
We also forget to mention one of the unhappy consequences that can happen: seeds or emaphrodite. Few growers have said they got seeds from a tiny amount of light
Bugbee mentions LED indicator lights as an example of sources that are too dim to matter (and perhaps thatās what @Poseidon1 was referring to). Light spill through an inlet could be different, and Bugbee describes an easy way to tell.
To my way of thinking, ignoring science and doing useless things in hope of better results is superstitious. But Bugbeeās findings indicate it does no harm in this case, so if some people feel better fixing non-problems, Iāve no objection ā so long as they donāt claim itās necessary.
Iāve seen anecdotal reports that excessive light at night during flowering can cause hermaphroditism, which will produce seeds if those plants arenāt yanked promptly. I havenāt found evidence of this, though, and ILGMās two guides on the subject donāt mention it:
Hermaphroditism in Marijuana ā What causes plants to go hermaphroditic?
How to Identify, Prevent, and Deal With Hermaphrodites in Your Cannabis Grow
So, the effect may be genuine, but like so many things involving cannabis, we donāt know for sure or what the threshold is. (Or maybe my internet search was inadequate.)
I am finding tons of stuff with this search:
.
ādo cannabis plants really need total darkness when lights are off? in nature they have the moonlighā
Also remember to use A.I.
I get lots of hits with that search phrase too, but only one that addresses the question (near the end of the article), and it cites Bugbeeās research:
Growing cannabis: Debunking the light leak myth .
The others address how long the dark period should be during veg and/or flowering and whether itās helpful to start flowering with an X-hour dark period, where X is either 24, 48, or 72.
If Iāve missed one thatās relevant, please provide the link.