Is there some database of plants and the soil-pH
requirements? The botanical name is usually
given on a tag when a plant is purchased.

Peter




If you are west of the Rocky Mountains in the U.S. or Canada, the
major portion of Sunset's "Western Garden Book" is a plant
encyclopedia that indicates climate, water, and soil requirements
for each listed garden plant. No, the soil requirements do not
indicate pH; but they do indicate whether a plant tolerates
alkaline, acidic, or saline soil.

There is also a Sunset garden book that covers the whole U.S., but I
don't know if it is as comprehensive. I would suspect there are
excellent garden books specific to other nations and climates.
Also, a good plant nursery -- not a hardware store or lumber yard --
should be able to advise you on whether a particular plant requires
an alkaline or acidic soil. Finally, there are various national and
international societies devoted to specific plant families: roses,
bromeliads, daylilies, orchids, etc.



PS. Wiki have something too..
http://en.wikipedia.org/wiki/Soil_pH

The notes at the top are right - this article is pretty weak.

The section on pH determination is quite misleading. The barium sulphate is
NOT the basis of the test as the test can be conducted without it. The
basis of the test is a mixture of dyes which change colour over a wide range
to give a gradation of indication of pH. Such test kits often include an
inert white powder to use as a backdrop to make the colour of the dye easier
to read against dark soil, Barium sulphate may be one such. Also litmus
changes colour quite quickly within a narrow range of pH so it only tells
you if the pH is above or below that point which is of very little practical
use.

The part on increasing pH is pretty bad too. You would have to be desperate
to use quicklime CaO as it may burn your plants (or you) and it will change
the pH very quickly which will shock the soil orgainisms. Calcium magnesium
carbonate is usually called dolomite not agricultural lime which is calcium
carbonate. Sodium, calcium and potassium ions do not raise soil pH, it is
the anions (typically carbonate) that often accompany them that do the job.

I could go on. I probably have gone on too much already.

D