Date: Mon, 8 Sep 1997 20:05:34 +0100 From: Laurent Legendre <laurent.legendre@univ-reims.fr> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg3438$foo@default> Subject: Back on Baking soda
Hi all,
I'd like to return to the baking soda story and add some personal thoughts
which actually derive from some experiments I conducted a couple years ago
and published in the french CP society newsletter. Judging from the number
of people interested to comment on baking soda, I guess I should have had
translated it into english for CPN...here it goes.
Basically, I grew D. capensis, D. spatulata and P. lusitanica, three
acid-loving CP's, on different in-vitro growing media. All derived from
MS-medium and differed by their dilution, pH and organic additives.
Basically, what one sees is that Drosera cannot stand high salt
concentrations and even prefer a 1/5 to 1/8 dilution of the standart mix.
P. lusitanica was less demanding. All three grow best under acidic
conditions at pH values which one could find in the wild. Organic
additives had a good effect on the red coloration of the tentacules of
Drosera. All of this goes with what we know, or think we know of CP's.
But still, I don't think Randy is doing that bad even though I've never
tryed baking soda, or feel like doing it for the following reasons.
Once, I tryed adding chalk to peat. A. Slack was talking of "peat rotting"
and I wanted to see it. At each addition of either hard limestone or
disolved matter, I measured the pH and waited one day between each
addition. Well, what you observe is that peat has a really high buffuring
capacity and that if the pH is braught up artificially it will tend to
return to its original value within days (by the way, peat is not as good
as a politician who once came to visit us at Purdue univ and who had told
us that, the science staff, that if he were to be elected, he would bring
the pH value of our lakes and rain water down to zero! ... poor CP's). So
my guess is that it would take a lot of baking soda to bring the pH high
enough to disturb our acid-loving plants and I doubt Randy does it. The
accumulation of salts would be more a cause of worry but sodium isn't as
disturbing as calcium or other divallent cation.
What most likely occurs as Randy (yeah, still you) is adding baking soda,
is that it favors peat degradation into smaller organic molecules (not
ammonia of course!) which will fertilize his CP's and probably give them a
more profond coloration as well as more growth. It ends up doing the same
as adding peat tea s, which I do to my CP's (Japanese green tea and
coffe also work good in my hands) and I prefer this later formula as it
avoids the salt problem. But heah, Randy, as they say, if it ain't broke,
don't fix it.
Before lifting up a new controvercy on CP fertilization, I'll add the
following. OK, CP's live on poor soils, and no CP stands commercials
fertilizers. But they stand and appreciate dilutions from them. I use
1/4 to 1/8 dilutions of orchid fertilizers once a month. Remember that
pure acidic peat prevents any breakdown of organic molecules. People even
find intact prehistoric bridges in peat. May be tney were here to observe
CP's...who knows. Moreover, farmers have long used limestone to fertilize
their fields via the destruction of organic debries. My guess is that
there is more organic food available to our plants in a bog due to
neighbouring vegetation than in our pots. One thing others may have
noticed is that, as you repot a Sarracenia into fresh medium, it firt grows
a lot and then slows down after a month. But if you add peat teas, quick
growth will continue.
Basically, what I'm saying is that our standart peat/sand mixture may
become too poor to our plants even though they won't stand rich soils and
by the way won't survive into house plant potting mixes as suggested.
There was a good study published in 1993 on that topic which basically
showed that Drosera do beneficiate a little bit from organic food in the
soil but do prefer bugs greatly, while Pinguicula and especially
Utricularia really beneficiate from rich soils...to the point Utricularia
may not beneficiate from bugs. In all of my Pinguicula mixes, I use some
house plant potting mix and it does help.
I appologize if this reply is a bit long and late but $ 0.02 of knowledge
cost more and more in France with the US $ sharply moving up against the
grench franc these days.
Happy growing,
Laurent Legendre.
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