Franz Heymann wrote:

There has been some nonsense spoken in this ng about the putative shelf life
of rooting hormones.
The following URL sets the record quite straight, quite unambiguously and
without prevarication:

http://www.pbi.co.uk/faq1.asp?productid=9

According to the manufacturers, the *minimum* shelf life of an unopened
bottle of "Baby Bio Roota" is 2 years. This figure is agreed by MAFF.
If the bottle is in use, the shelf life *may* be shortened due to the
accumulated contamination from soil and plant debris.

I have written to the manufacturers about the shelf life of the powder
"Strike", and will report when I have something to say about it.

But are you assuming that all the preparations sold domestically are
the same? Surely some may have varying shelf lives depending on
preperation. If in doubt do some with some with out..
As others have pointed out, the techniques and mechanics of the rooting
powder (or solution or gel) ingredients are rarely explained..

I spent a few months in a lab learning the basics of IAA & IBA auxins
the main 'hormones' (scientists apparantly STILL aren't sure if they
strictly are hormones;-) or so we were taught) use for commerial
propagation. As we discovered in some basic lab experiments (repeated by
millions of students all over!) the amounts vary and effects reverse
depending on amounts/concentrations etc.. Ie a tiny amount of one
substance may induce rooting, but may retard it in a larger amount. And
of course this varies from species to species, plus you have other
effects such as temperature, humidity, soil bacteria etc..


Makes you remember how incredible life is a reproducing itself with no
assistance whatsoever!-)

Moving back to the domestic scene Geoff (Hamilton) used to recommend
mixing powder with a little meths for even coverage of cutting bases.


//
Jim