Brian said:

There is a mis- understanding. The poster said about calcium chloride
which they use to melt ice on the road. It is not rock salt (sodium
chloride) The calcium chloride it usually small round white balls. It is
usually sold to be yard and concrete safe, unlike road salt. I may be
wrong but pure calcium chloride contains no salt like road salt.


Calcium chloride would technically be 'a' salt which is sometimes
used on roads, but it contains no sodium chloride (which is a completely
different salt.)

To be pendantic...

Compounds of elements from periodic table group VIIA (the halogens, or
'salt-makers') with metalic or non-metalic elements or simple compounds
are salts. The most noteworthy halogens are fluorine, chlorine, bromine,
and iodine. Halogens are highly reactive and do not naturally occur in
elemental form.

Sodium chloride is a salt (in the vernacular, it's THE salt). It's mineral form
is halite (typically referred to as 'rock salt') which can be mined from large
deposits (the proverbial salt mines). It's only use in the garden is for controlling
weeds and disease in asparagus plantings, though this use is controversial.
(Asparagus is naturally tolerant to sodium chloride, just like the rugosa roses
mentioned earlier in the thread.)

Calcium chloride is a salt. Calcium chloride is more expensive than sodium
chloride because it is manufactured rather than mined. It is effective at lower
temperatures than sodium chloride and it is somewhat less damaging to
road surfaces and structures (there is a new liquid application method which
might make it substantially less destructive) . Calcium chloride could possibly
be useful in the garden as an emergency source of calcium.

Rather out of place in the middle of July, an article about the various sorts of salts
and chemicals used for pavement deicing (with a list of salt-tolerant trees and
shrubs):

http://www.ianr.unl.edu/pubs/horticulture/g1121.htm
--
Pat in Plymouth MI

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)