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RE: 24/7 day length query
>Has anyone tried odd lighting schemes? Like 24 on, 24 off. Or 6 on, 6 off.
>Something that isn't 10-14 on and 10-14 off. What were the results? I
>realize that the lighting timers are based on a 24 hour clock and that makes
>the 12-12 very useful, but has anyone played around with the day
Light timers are based on a 24 hour clock because that's (approximately)
the length of a day on earth. For some really odd reason, plants that have
developed on earth have also adapted to this timing.<g> While I'm not sure
whether or not anyone has duplicated day length studies on strictly aquatic
plants, most of the plants we use in the aquarium AREN'T strictly aquatic,
and many, many studies have been done on the affects of different day/night
cycles on various non-aquatics.
It is absolutely true that day lengths are more important to some plants
than others. It is also well known that day length (actually, I believe
the more important factor is night length, if you want to get nit picky)
affects the flower production in many species. That's how they get all
those Easter Lilies blooming EXACTLY in time for Easter, even though the
date of Easter varies quite a bit from one year to the next.
IN GENERAL, the plants that we use in the aquarium are tropical plants.
(they come from areas that have water temperatures similar to those we
maintain in the aquarium) IN GENERAL that means that in nature they are
adapted to day/night periods that are no shorter than 10 hours, and no
longer than 14 hours per cycle. The closer you get to the equator, the
less day/night difference there is. One of the things that was quite novel
to us "northerners" during our trip to the Amazon was the absolute
regularity of sunrise (6 am) and sunset (6 PM). We're used to the "feel"
of warm weather meaning LONG days!<g> Having the day and night of equal
length is such a novelty in northern cultures that festivals have grown to
celebrate these days!
There are some plants that will continue to do fine on a 24 hour light
cycle, or any other completely artificial light cycle. There is a larger
group that will continue to "survive" under these conditions (plants are a
really tough lot!) though they may not thrive. If we are attempting to
provide good growing conditions for a maximum number of species, it makes
sense to stick to a reasonably natural photo period, namely, between 10-14
hour of light per day.