The following is a cross post with permission from the writer. I thought it was very interesting!
(quote)
Hi All:
I want to pass on a culture tip that might be of interest to many of you. A
little background first. In an earlier incarnation I had a very large
collection of staghorn ferns and was growing them from spores. Over time my
mature plants lost their good green color and did not have the luster they
had once had. About this same time I learned that many orchid growers
routinely acidify their water if it is neutral or basic. Delving deeper into
this, I learned that they used either citric or phosphoric acid to
accomplish this as neither is harmful to the plants at the concentrations
used. At that time I had all of my plants on an automatic watering system
and kept fertilizer concentrate in the reservoir. Having access to a well
equipped chemistry lab, I had the head chemist determine precisely how much
phosphoric acid I would have to add to my concentrate to give me a delivered
pH of 5.6-5.7, which is generally accepted to be the "normal" pH of
rainwater, with which these plants are watered in the wild. ( I chose
phosphoric acid rather than citric as the phosphoric would also serve as a
nutrient, whereas the citric doesn't.) Believe it or not, there was a
profound improvement in the appearance of my plants literally overnight
after their first watering with the acidized water. As my current tap water
has a pH of about 7.0 -7.3, and I constantly get a salt residue on the top
of the soil iof my AVs, I hearkened back to my acidification of my water for
my staghorns, as our species AVs are also watered with rainwater. Using an
inexpensive pH meter acquired at a local nursery and designed for testing
soil pH, I have determined how much phosphoric acid I need to add to a gallon
of fertilizer mix to produce a pH of about 6.0 (I shoot for this due to the
inaccuracy of the pH meter). I used a 20 cc hypodermic syringe to measure
the phosphoric acid. The acid is "normal' and is obtainable at Home Depot,
etc., as a tile and grout cleaner. It is pure phosphoric acid. I have been
using acidified water on all of my AVs, mature to "mouse ears", for a month
now with no apparent adverse impacts. Another "Believe It or Not", I again
saw an overnight change in the leaves of the first test plants that I used
it on. They took on an indescribable "glow" that makes them really stand
out. Moreover, my plant growth rate has increased, including plantlets where
it is most noticeable. I both tap water occasionally to insure that my wicks
are working, and have acidized water in my reservoirs. I would encourage
those of you who are using neutral or alkaline water to give this a try to
see what it does for your plants.
Happy Growing,
Frank
Visit your group "VioletReflections" http://groups.yahoo.com/group/VioletReflections/ on the web.
(end quote)
There was a follow up message.
What a great tip, Frank, thank you! My question is, do you still
fertilize along with the phosphoric acid?
(reply)
Yes. Thanks for the question as it reminded me that I left out a very
important point yesterday. In determining how much phosphoric acid to add,
you need to do this on water that already has your fertilizer in it as some
fertilizers themselves may change the pH slightly. There is one downside to
adding the acid that I have experienced; it causes the blue dye in most
fertilizers to fade in short order. To compensate for this, I add one drop
of ChefMaster Indigo Blue food coloring to a gallon of water. This is
available at cake decorating supply stores. It does not hurt the plants (the
Munk's used it for years).
Frank
Additionally, here is an article to read "Saintpaulia: Taxonomy, Ecology and Distribution by Jeff Smith
http://www.gesneriads.ca/saintart.htm
If you are interested in more, it's easy enough to join the Violet Reflections Yahoo group. I always read the digest and you can follow up on this thread.
