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

[APD] The problems with generalizations

Laura Burbage wrote:
> I'd like to suggest that we be a tad more careful with
> generalizations on the list.  We seem to forget that
> different species of plants hail from different
> places, all with different environmental conditions.

In addition to what Thomas has said, I would add that there are many
generalizations that are very useful for practical aquarium management.
There are some plants which are more difficult to grow than others and so
what Laura may be getting at is that we should really elaborate on those
particular plants. At the risk of generalizing, the discussions in this
forum are frequently oriented towards Question & Answer and are often
centered upon algae management, that being one of the biggest problems in
aquatic horticulture once you get past the basics. Generalizations help to
answer these questions but see below.

If you are looking for advise about a difficult plant ask about it

George B once quoted a table of LSPs & compensations points for several
aquatic plants. I bet its one of the reasons that George is so stingy with
his lighting levels. Could it be that he's onto something? George: you're
far too quiet these days. Have you still got that table? come on old man! I
hope the power cables haven't put you in hospital (again). ;-)

The place where we have generally gone wrong (oops another one) is in not
advising the reduction of lighting intensity to at or below the LSP when
attempting to manage algae. The LSP is an empirical upper limit where all
other growth factors are supplied in super-abundance. Its probably well
above the actual photosynthesis maximum given the relative scarcity of
nutrients (excepting Tom's high N+C regimen) in our aquariums. I think he's
also mentioned that substrate Fe can be limiting. Based on my own
experiences, I would agree with the importance of substrate Fe as well as N
in order to limit N availability to algae.

There may be extremes of water hardness where an excess of K, Mg or Ca can
interfere with the uptake of one of the other cations. There may be some
plants with adaptations that permit it to deal with an excess but if these
minerals are kept at a suitable concentration and more importantly, at the
appropriate ratios, then, in general, all aquatic plants should not have a
problem. There has been considerable speculation in aquarium literature that
certain plants require a certain hardness or lack of hardness. AFAIK, the
current wisdom is that this is untrue.

Specifically, it was thought that A madagascariensis required soft, pure
water & low temperatures in order to thrive. I can definitely say that the
key for success with this plant for me has been to provide it with a steady
supply of hydroponic N. I don't know from my own experience or from anything
I've read if there is a possible role played by certain impurities in
triggering changes in the plant's growth or preparations for the dry season
(if it does). I would sure like to read more about the natural habitat of
this plant in order to make more speculations. I do know that we can keep it
going well under nominal conditions provided that a) N is available b) I
don't disturb the roots of the bulb. I'm not keen to explore all the factors
that might lead to its demise, for obvious reasons. If I manage to stimulate
another bloom & get enough viable plant-babies, I might do a little
investigation but I'd probably be too greedy & want to pot them all up for

New topic: difficult plants & keys to success

Scott wrote:
> Seems okay, as a general rule of thumb ;-)

This would probably be just as funny without quoting Laura's entire posting,
generally speaking of course... ;-P

Steve P in Vancouver with the sun finally showing up!

Aquatic-Plants mailing list
Aquatic-Plants at actwin_com