"thesquire" wrote in message
...
I have been told on good authority that the talc powder based
preparations lose their effectiveness after about eight months, even
if kept in a closed container and refrigerated.


The manufacturers own website for "Strike2" from PBI
gives a minimum stored shelf life of two years and
at least another two years after opening if
uncontaminated. They don't say anything specific about
optimum storage conditions, but keeping most things
organic and chemical in the dark (to use the technical
terminology) away from UV light, and relatively cool
seems to prolong their lifespan.

quote

An unopened container of Strike2 has a minimum shelf
life of two years. Strike 2 is registered for sale under
the guidelines set by the UK Regulatory Authority and
as part of this registration such storage stability
must be proved. Once a container has been opened the
shelf life can be just as long, however, it may be
necessary to replace product in shorter time spells
due to contamination from soil or plant debris in the
powder.

http://www.pbi.co.uk/products/239/1/?Strike+2

/quote

You'd imagine PBI would be keen to promote as many replacement
sales as possible - and so this can presumably be taken as a
conservative estimate of the product's longevity.

The fungicidal component in rooting poeder is apprently more
persistent, and so this alone may account for continued success
when using much older powder - up to 8 or to 10 years old in my
case. Or maybe its benefits are overstated for some material in
any case.

When this question was asked on Gardeners Question Time in 2002 two
of the panellists admitted they'd stopped using it years ago
with they claimed, no appreciable difference.

http://www.bbc.co.uk/radio4/gqt/fshe...heetsq12.shtml




michael adams

....





I've checked on my containers and none have any dates. Are they
supposed to ???

Where can I get some 'fresh' rooting powder from ???