[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Crypts enjoy strong light too

Hello ADPers,

As a consequence I thought I'd add something here,

I just happen pick up and was reading in Aquarium Plants by Karel Rataj and
Thomas Horeman and found a short comment about shade-loving plants.  They
specifically mention the conditions some cryps experience in nature in
Singapore.   Basically they present the question; do shade-loving plants
exist?  I'm quoting from page 20, "Many experts believe that shade-loving
plants do not exist.  Among aquarium plants the cryptocorynes have the most
familiar reputation as shade-loving plants.  It is true that in nature most
of the them grow mainly in shaded situations where no other low-growing
vegetation exists.  Do they live in deep shade because it meets their
requirements best or because thy have been forced there through competition?
In [their] opinion there is no doubt that they have been forced into the
shade."  ....[they go on to say]...the soil is poor in the tropics therefore
plants with extensive root systems out compete/suffocate other plants like
cryps with non-extensive (poor) root systems.  Essentially cryps are forced
to live in shaded areas where other plants can not exist  and consequently
in subdued light.

They go on to point out that in shaded areas "water holds its good
qualities".  "If water is alternately sunlit and shaded, sudden changes take
place.  There are changes in the number of species of protozoans, algae and
bacteria.  In consequence both chemical and physical qualities of the water
change and these changes effect a negative growth in the development of
plants."  We have all seen or read about  the dreaded "crypt-melt" when we
introduce sudden water, fertilizer, lighting changes in our tanks or even
just moving them will upset their "state" and they start to deteriorate.

Rataj and Horeman go on to point out that in our aquariums we should strive
to provide a "constant and favorable"  balance between light, nutrients and
water-quality throughout the year.  "Do not be afraid of plenty of light for
your "shade-loving" plants but protect them from fluctuations."  I am sure
many people on this list, including myself,  have demonstrated exceptional
growth and vigor with various cryps in 3w+/g lighting.  Although this is
sometimes after a meltdown and once the cryps have become accustom its new
conditions.   In my experience cryps tolerate only temporary nutrient
deficiencies.  When I see small holes forming in the leaves this is a good
indicator of Mg deficiency.  My water is very soft (2kH/1gH) so I add a 1/4
tsp. of lime with water changes for a while.  I have a feeling that my heavy
snail population actually effects my Ca/Mg levels but they are worth it!

Tom Brennan
brennans at ix_netcom.com


To: aquatic plants digest <Aquatic-Plants at actwin_com>, Neil Frank
<nfrank at mindspring_com>
Subject: Re: Crypts enjoy strong light too
From: Steve Pushak <teban at powersonic_bc.ca>
Date: Wed, 13 May 1998 21:51:09 -0700


Neil wrote:
> Crypts can tolerate weak lighting... true. Crypts can benefit from
> lighting... true. But not all crypts enjoy the same degree of lighting as
> other plants. For this reason, commercial growers have to control the
> amount of natural light they give crypts.... some more than others. This
> despite the VERY rich substrates that they use.

Could you be more specific about which Crypts must have controlled
lighting? I suspect the Crypts might saturate their rate of
photosynthesis at about 10-20% (?) of full sunlight (I'd have to double
check the figures Dave Huebert quoted) so they would derive little
benefit of lighting in excess of this. I think that when you refer to
controlled _natural_ lighting, you mean from sunlight and this would be
considered STRONG lighting relative to artificially lit aquaria. Are you
saying that some Crypts actually suffer from too strong lighting? I can
see that you might have problems with temperature and moisture content
if you were growing emersed plants; is that what you refer to Neil?
Which Crypts are the ones which suffer the most?

I think we should not advise hobbyists that they must use LOW lighting
for Crypts since that term usually refers to artificial light, not
filtered sunlight!