"Deight" wrote in message
news:C5rLg.521189$IK3.419753@pd7tw1no...
Does anyone have suggestions for a good quality PH meter.......Digital or
analog meter, doesn't matter, provided that it is reliable. The one I got
from my local garden center reads 7 for all areas of my garden. I knew it
was a dud when I placed it in pure lime juice, and it still read a PH of
7.


All the meters that I know work on the same principle - bascially, they read
the electric potential between two parts (metals) of the shaft, or the
electric potential between two side-by-side different-metal shafts, using
the soil.
Ph 7 is no potential (zero voltage).

It's a very small potential, and there has to be enough of a current flow in
the meter bridge to register.
The oxide on the metal and/or the lack of fluid in the path both reduce
the flow available for the meter. However, too damp soil or a dirty
insulator, and the path is primarily in the fluid/dirt on the insulator
instead of primarily through the meter.

First, you need to wipe the stem clean before using, but not damage it or
smear metal or dirt across the insulator separating the two metals. Wipe off
the crud at the insulator with a wet kleenex, wipe dry, and then use a
dollar bill or brown paper toweling to remove the oxides right before
reading.
Turn around the shaft to wipe it, rather than wipe along the shaft.

Second, the soil needs to be damp but not wet. The meters don't read mud
well.
City tap water has a ph around 8.4- 8.7, depending on the time of year,
so if you put it in the soil with tap water, you can read higher ph than the
soil. I read a day or so after a rain (NOT sprinklered), or I put a few
drops of distilled water in the soil and mix it up before reading.

Third, if you don't get a reading, the soil is too dry, too wet, the probe
is dirty, or the meter is broken..

So wipe it per above and dampen the soil with distilled water, and if it
still won't read, then test it by wrapping it with a damp napkin sprinkled
with baking soda (ph about 9-10) - and then clean it and test it again using
a napkin dampened with vinegar, soft drink, or beer (ph 3-4).
If it doesn't read a damp napkin, take it back to the store with a damp
soil sample, and get one that works on the sample.

fwiw

Any ideas would be greatly appreciated.


Deight.