Re: Shouldn't low lights cause better growth?

["Robert H" <robertph3 at attbi_com>]

>>I spent a few hours today reading up on what lights grow what plants and
trying to figure out how best to set mine up, and all I got was equal
portions of differing theories. I think from what I have been observing in
my tank though that if your lights are relatively bright, the plants have no
need to grow upward, as they get sufficient light where they are, so they
are healthy as mine are, but stay static in size. If your lights are dim, or
there is a great amount of floating particulates, then the plants have a
need to grow upward in order that the light may be better utilized. It just
seems that the evolutionarily-affected design of most living things leans
toward a miserly approach to functioning, so that if there was no need for a
plant to grow upward, it wouldn't do it "for the helluva it." Having just
started out, I wanted to grow the stem plants a lot, and keep trimming them
as they hit the top of the water and plant the cuttings etc. so that I could
save money on pl!
ants and keep the growth thick. The problem was that all but the h.difforms
were looking great, but not doing anything, and I think the 4 GE Daylight
Ultras are to blame, as they were satisfying the light requirements all too
well.
What do you think?<<

You have things a little backwards. Plants grow in the direction of the
light. Brighter light increases the metabolic/photosynthesis rate, which
increases the growth rate. Aquatic plants also naturally reach toward the
water surface so that they can flower. Creeping, low growing plants in
nature only grow in very shallow water. You wont find 2" high glossostigma
growing in 2 feet of water in the wild. I grew Wisteria, (hygrophila
difformis) under very bright light, and the stems reached over 20" in
height.

If your Wisteria is staying low it is probalby because the stems are not
growing thick enough to support the weight of the plant. This can happen
from a nutrient difficiencey, poor light, or simply from over pruning
without throwing out the original rooted stems.

Robert Paul Hudson
http://www.aquabotanic.com