[APD] RE: Generalizations/Plantically Correct

["Thomas Barr" <tcbiii at earthlink_net>]

>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. 
>While a particular species may be quite adaptable,
>some are not.  This can even be true within a genus. 
>For example, Bacopa caroliniana and B.
>madagascariensis both grow better in soft water
>(Kasselmann, C. 2003.  Aquarium Plants.  Krieger
>Publishing Co.).  However, Bacopa monnieri can grow in
>either soft or hard water (also from Kasselmann
>2003).  Brasenia schreberi (water shield) is a
>difficult plant to grow, and requires very soft water
>(Rataj, K. and T. J. Horeman.  1977.  Aquarium plants,
>their identification, cultivation, and ecology. 
>T.F.H. Publications, Inc.).  

Many of these suggestions are from wild natural systems, now are our tanks
even close to that type of habitat?
They are also suggesting that the plants are found in these locations, but
it does mean the plant prefers to be there or it is just where the plant
can live at that time in that space?  

What plant _cannot be grown well_ in a flourite substrate with a little
peat, CO2, decent lighting(say 300 umol/m^2/s^1), routine NPK/trace
additions(sub or/and water column) with a KH/GH of 5?
Name one plant species that must have other conditions to do well?
I don't know of any.

There are some things that can be generalized generally:)

I've grown the above species and about 250+ ssp in rock hard water. 
There is no soft water plant I'm aware of. I would challenge that a
submersed plant prefers soft water, actually, I would argue that a plant
prefers harder water and grows better due to the total DIC being HIGHER in
harder waters than softer water where the CO2 level may go to zero, at
least in the hard water, there's some HCO3 to use for a carbon source.See
Van, Haller, and Bowes, J. Plant Physiology 1976 58, 761-768, specifically
pg 765 for more on that arguement.

 My tanks have had some extreme hard water taps over the years, I presently
have very soft tap water. I have the same growth of most any species you
can care to pick.I also live in a region where I can go 20 minutes away and
see pH4.7 -5.0 and no GH/KH and good plant growth... to the other extreme
with hard water systems in the 8-10 range and pH's at 7.4-8.2 also not far
away. Guess where the plants do best? 
This is in natural systems.

I've had tanks full of "supposed prefer, or soft water plants" with
extremely high GH's and KH's.
So do many folks, I'm not the only one. I lived where we had dramtic tap
water differences close by. 
RO makers likely hate me.  
Also see Claus' write up on the Tropica site about South American regions
where aquatic plants thrive in hard clear waters as well. The same is true
here in FL.

>Different species can also have different lighting
>requirements.  Some shade plants will not survive high
>light intensity, while full-sun plants will not
>survive shade. (Kasselmann 2003)

Such as what plant? Are you generalizing?:-)
I'd certainly argue MOST aquatic plants are shade plants. So would Bowes,
Haller, Hoyer, Brown, Fox and anyone working on aquatic photosynthesis in
macrophytes. If you look at the light saturation points(LSP's) for many
true aquatic plants, you'll find a range around 250-400 umols/m^2/s^1, vs
full sun at 2000 umols/m^2/s^1. Some plants will be exposed to higher light
levels, but they are inhibited by very intense light(destruction of D1
proteins, Photorespiration etc).
The LCP's are very low, some plants down around 10-20 umols ranges. 

They have to be shade plants with LCP's with good reason=> turbidity
changes, water level fluctuations, other plant/algae light competitors
present.
If they need a lot of light to drive PS, they will likely not make it in an
aquatic environment over time. 

>Different species also have different substrate
>preferences.

Well, I'd certainly challenge this one. There is a HUGE difference between
a natural system where a plant is found and what it actually __prefers__.
It's living there because it can survive there, not because it's the place
it "prefers". Too many assume because it's found somewhere in nature, that
this is what's best for the plant's growth and health. This is not true.
Serpintine soil plants are not there because that's what they prefer, they
are outcompeted by other plants eslewhere. The same can be said for many
aquatic plants.  

Hydroponic culture: look at many of the aquatic plant growers in the USA,
they raise a large amounts of aquatic plants hydroponically, so does
Tropica and a number of folks on the APD. Flourite, onyx sand etc all do
very well for plants in tanks if they have a small/moderate amount organic
material in there. I have not found any exceptions to this generalization.
You can put a little more in the substrate or a little more in the water
column, but ultimately you will get nutrients from both nutrient sinks.     

 > Some plants grow well in sand, some do
>not, and require at least some mulm if not silt and
>clay particles (personal observation).  Different
>plants can also have different nutrient requirements
> in both water and substrate.  Different plants have
>different temperature tolerances.

Well, if you keep the plants in the 20-21C ranges, they do fine, most
things will be dandy and with a couple of exceptions at higher
temps(Aponogeton etc), most of the 300 or so species do just fine at 25C.
There are some plants that like it colder but few people keep tanks that
cold with plants, eg Lobelia in Danish streams at 9C. But I'm generalizing,
someone might keep coldwater plants(are you in the house?)

>I think this is especially important when we consider
>that people (including myself) read the list looking
>for information to use on their own aquariums.  When
>giving advice to individuals, I think we should be
>careful not to say ?Plants like condition X?
>or ?Condition Y always helps?.  While it may help the
>plants of the individual in question, it may not be
>advisable for others reading the post.

In some cases but I think this is due to other factors(their CO2 is lower,
lighting different, water change routine different etc)
Generally this comes out if they really want to get to the bottom of an
issue with health, algae, general good growth that does not make sense at
first glance.
People use to say these things and raise these question about substrate,
soft/hard water etc, PO4 causes algae etc, but if you go about things
critically and try them yourself, you'll find that plants, although I will
say there's always at least one exception to any rule, you will find that
the issues are not generalizations, but rather something they over looked.
It's easy to prove what something is not vs proving what it is.

You say Bacopa perefers soft water, why can I grow bucket loads in rock
hard tap water? 
I also have grown it the same way in rock hard water. So is what you say
true?
The only notable differences are the KH/GH. 
Or pick a plant that has to have a rich substrate in order to grow well.
People say that Crypts and Swords must have rich substrates but I grew them
like crazy and with good health with RFUG and no substrate amendments. Not
just one species but many from both genera.  

>  Better
>statements might be something like ?The plants you
>have prefer condition Q?.

 I think plants are much more alike than different as far as needs.
There are subtle differences such as Anubias being able to handle less
light in a dark corner than some plants, but any generalization is going to
have that issue to some degree.You work through a problem with people, not
solve it in one single post. If they have exceptions etc, it will come to
light through trying to figure out what is going on.Most folks ask the
questions till they are satisfied and feel they have figured it out or
cannot go further.
I've tested what I say and have had many species to experiment with over
the years. I've tried a lot of things.  
Some of things I've said in the past have been unpopular at the time...but
they were true. 
  
> I think we should even avoid
>saying ?most plants available in pet stores?, since we
>all know that many (not all) pet stores will sell just
>about anything if it sells well.

Very true.

>I am particularly bothered by blanket statements
>like ?P substrate is the best?, 

Well you may want to try them before making this statement:)
I've done a lot with substrates over the years.
Soil, peat, sand, laterite, cables, RFUG's, deep, shallow, flourite, Eco
complete, onyx, flora base, jobes, agar, kitty litter, clay balls, a number
of plant tabs, snail poop, mulm, manure, river sand, cork, wood, rock and
other concoctions.I have not included saltwater systems but that's another
area I get into. 
If you spend 10 years using a substrate, you get to know it pretty good.   
Also, what ruler do you use for comparisons?
A nutrient absent/poor substrate is, IMO, the best starting place and build
upon that.

>or ?Q condition is
>necessary?, as they can be very misleading. 

True. 
You need/should be specific in the question if you want a specific answer.

 I would
>much prefer to say ?R works for me? or ?I have seen
>species S grow well under Y conditions) or ?author Z
>or company S says that Y conditions are required for
>this plant?.
>Laura

It seems that the books and other older, outdated, poorly supported
references are the dogma to me. If I had a nickle for everytime someone
said excess PO4 caused algae, you need soft water to do well with plants,
this plant "prefers" high light, red plants need more iron, too much iron
cause algae, large water changes are bad for a plant tank/fish(I'll make an
exception for non CO2 plant tanks) I'd be a very rich person. If I could
count the myths.

But I know what you are trying to say about generalizations. When I make
them try to back them up both with expereince and with science and research
and if none of that works, I'll come up with a test/method that will answer
the question at hand(hopefully). I cover my butt pretty well.

I have no issue stating excess PO4 is not causing algae in a CO2 enriched
tank or that soft water is NOT needed for some plant. 
 Adding PO4 works for me, Flourite/Onyx works well with some 300 species of
plants and GH from 3-25 works with 300 ssp of plants, plant X likes lots of
CO2, I have seen ssp Z grow well under high, med and low light, Bowes,
Haller, Fox say true aquatic macrophytes are basically shade plants.  But
there are always exceptions:-) I keep a look out for those and want to know
about them to see if they are true or not. 
So when a new plant comes down the line, I like to try it to see.Maybe I'll
get lucky.
 
I see many more similarities with aquatic plants, methods and habit the
more I know and understand about them.
I find many researchers also have this attitude but we tend to be specific
about certain plants we have grown. Having grow many on the years, I have
an edge but there are __many folks__ out there that have grown close to 100
ssp or more and have done well with them. 
It's a disease called "Collectoritus". I no longer have it, but many are
inflicted.  

I don't trust many books out there on hobbyist growing aquatic plants. I
know some of them are plain wrong and they never tried to figure things out
critically first and made a balnket statement. The classic was excess PO4
causes algae problems. The other is soft water "preferences". I see no
evidence for either of these statements for planted aquariums.    

That word "prefers" will get you into a alot of trouble:)  

Regards, 
Tom Barr     


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