schreef
Hmm. Assuming somebody is providing water and other reasonable care to
these plants, they will respire for 29+ days of the month, and
photosynthesize around the clock for the other 14.5+.

* * *
Yes, it is all in the assumptions. And OP provided very little in the way of
common ground to base assumptions on.

* * *
They probably
won't grow twice as fast during the round-the-clock light phase than
they would with 12 hours on and 12 hours off, but they will grow at
least somewhat more. Whether they can accumulate enough photosynthate
to survive the dark half of the cycle is problematic, but they will
certainly get etiolated and weakened, and do a poor job of removing CO2
to purify the air for the humans in the habitat, much less provide them
with vegetables. If the plants are being used to purify waste water,
your habitat will end up in deep... umm... unprocessed waste water for
half the month.

I think we may be saying the same thing, but it's hard to tell, since
the word "day" is being used for three very different amounts of time
here.

* * *
A day is a light and darkperiod (i.c. a month on the moon). However, as soon
as people actually go and live on the moon an artificial day will be
established (probably of 24 hours).
* * *

It's a lot of fun to speculate about, however.

* * *
Possibilities are endless, which makes sure that SF stories that
conscientiously try and get it right become unreadable quickly.
PvR