I have a pH meter for my hydroponics. I am about to give up on it because
the electrodes do not last long enough to cover their high expense. When I
have gone through my supply of electrodes, I will rely upon pH paper.

In regard to paper, I find the Hydrion paper to be almost useles because the
printing for color matching is so atrocious as to be almost useless. there
are other papers of higher qiuality, and cost, using multiple indicator
dyes, that I will use. I can get 300 strips for the price of one electrode.

One problem with pH tedstiong of soil is that you count on the buffering to
maintain the pH as the soil is mixed with water. I do not understand that
process at all.


Agreed.... I think when we talk about pH in the soil, it is akin to
a differential equation in which you have a dynamic process. The pH
at any given moment depends on the amount of water, because the water
will dictate the nutrients that are bound to soil particles or in
solution. I would expect this to vary with rainful and evaporation.
Maybe the pros specify pH in terms of parameters like water potential
and cc's of water per liter of soil, or some such. pH by itself without
further specifications seems an inadequate characterization.

I have thus far measured pH by collecting a soil sample and running tap
water through the soil. I collect the flow-through and I look what has
happened to the pH of the water before and after it was added to the
soil. I only add enough water to get sufficient volume to measure
with a lab pH meter. We can say from a liter of soil I add enough
water to collect 20 ml. It is helpful, in a separate experiment, to
weigh the soil before and after draining to measure the maximum water
it can hold.

Dominic