CPs and pH

From: Ivan Snyder (bioexp@juno.com)
Date: Thu Dec 16 1999 - 10:28:27 PST

Date: Thu, 16 Dec 1999 10:28:27 -0800
From: Ivan Snyder <bioexp@juno.com>
To: cp@opus.hpl.hp.com
Message-Id: <aabcdefg4157$foo@default>
Subject: CPs and pH

Hi CPers,

     I enjoyed the Drosera anglica article in the latest issue of CPN
written by Don Schnell. I can add something here along the lines of what
we have recently been discussing regarding water purification and pH. D.
anglica and D. x anglica are as told to be a result of the cross D.
linearis X D. rotundifolia. The D. linearis parent in the cross is a
peculiarity amongst sundews in prefering to grow in marl fens. Marl is
chalk ( Calcium carbonate ) and is alkaline, having a pH of about 8. This
high pH would mean death for most sundews. Another exception I know of is
D. indica which I have planted in soil that killed others. I have been
experimenting with rainwater rinsed beach sand for planting. This is a
plentiful and inexhaustible resource where I live. Beach sand also has a
pH around 8 due to the ground up sea shell it contains. I have found that
D. linearis grows well in just beach sand and watered with rain water
which I collect for all my CP. I have recently cross pollinated D.
rotundifolia and D. inearis myself and have sowed the seed on this soil.
I figure only the hybrids will survive. I have also planted a number of
butterworts in beach sand with good results.

The municipal water here in LA county is extremely alkaline and unclean.
I don't drink it and instead get all my drinking water from vending
machines commonly found outside supermarkets. I used to use this on my CP
until I realized it was possible to collect and store enough rainwater.
The machines purify by deionization. I test the pH with a cheap $1.99 kit
purchased from an pet/aquarium shop. With the kit you add one drop of
Bromothymol Blue to a half vial of sample water. The solution reacts and
changes yellow for acidic, clear for neutral, and blue for alkaline.
Rainwater tests yellow. The deionized water I buy at 25 cents a gallon is
yellow if the machine's filter has been regularly replaced ( I have
caught them a few times ). Tap water is dark blue. You can also test soil
materials by mixing it first with neutral or acidic water, and then
sampling the water. Surprise!, horticultural sand is actually alkaline,
not good for sundews, but works well for butterworts. Sandblasting sand
or Play Sand which is composed of silica is neutral.

Besides sundews, we here in LA know of some other CP that will grow with
tap water. Most Nepenthes do. Sarracenias and butterworts tolerate it
fairly well for a time. I think with butterworts it is not the high pH
which does them in but rather salts in the water like Sodium Chloride and
Alum. If you have really good vision you can see in the photo of the marl
bog in the CPN article that there are Sarracenia purpurea also growing
directly on the marl soil. I know that Pinguicula vulgaris also grows on
alkaline soil. I have tried transplanting CP to year round seeps in my
area. Aside from the water being extremely alkaline, there is too much
alum ( Sodium Aluminum Sulfate ). Some plants may be tolerant of high pH
but salts will accumulate to lethal levels, especially in pots

Ivan Snyder
Hermosa Beach

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