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Re: Crypts enjoy strong light too

At 09:51 PM 5/13/98 -0700, Steve Pushak wrote:
>Neil wrote:
>> Crypts can tolerate weak lighting... true. Crypts can benefit from stronger
>> 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 is
>> 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 would like to see these figures too. What I was referring to was filtered
sunlight.... while some nursery grown plants get full sun, most get
filtered light. After all, many plants grow in streams under the tree
canopy. The degree of filtering varies with the plant. I don't have a lot
of data... but I do know that some nursery  crypts grown submersed outdoors
are under 80 percent shade screen. Other plants are shaded less. Most
Cryptocoryne are commercially grown emersed... either outside in shaded
cement enclosures or indoors hydroponically. Only a few are grown
submersed. The latter include C.affinis and C. crispatula var. balansae and
C. crispatula var. crispatula (formerly called C.retrospirilis). I have
been told that in nature some crypts (perhaps different species) are found
growing in full sun. Because of the diversity of plants in general and of
crypts in particular, I am very relucant to make generalizations. 
 
>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!

Did I say that? I thought I said
"Crypts can benefit from stronger lighting... true."

However, I should have modified my second statement to 
"But not all crypts NECESSARILY enjoy the same degree of lighting as other
plants."

For balance in this discussion, lets also be clear that while more might be
better than less, maximum light is not needed or always desireable (extra
heat, expense, more pruning, more work, ...) Let's also not leave the
impression that our budding aquatic gardeners need to cram as many bulbs
over their tank as possible. I am very satisfied with some of my tanks with
1 watt per gallon and also happy with the ones with 2-3w. (I never tried
more with artificial light) Nevertheless, it would be interesting to
observe the behavior of individual crypt species under different light
intensity _and_ different spectra (say, higher in the red only)... grown in
monoculture AND in combination with other plants.

Neil Frank, AGA


>
>Steve
>
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