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Re: mold

>Richard Grazzini wrote:
<snip>
>Your hormone dip is also not sterile.

Though, many rooting hormones (powders) do have fungicides mixed in with
the hormones to prevent fungal problems arising from the powder itself.
So no, not sterile, but also not 'contaminated' with fungus.

<huge snip>

>After my experience with flasking orchids, which included 10 months from
>pollination to seed pod, $35 for nutrient agar, an entire morning spent
>boiling agar, readying flasks, cooling, cleaning the pod, maintaining a
>sterile field, and finally the sowing of the seed, all done in an
>aquarium tipped as you stated above.....I saw mold and fungus infect
>every last flask.  Once again. sterile is sterile.  No middle ground.
>I see no advantage to trying Mickey-Mouse techniques for serious
>business.  If its a hobby, that's one thing,  but the time and effort we
>put into the orchids taught me that it wasn't worth it.
>>
>> Rick Grazzini
>> Centre Analytical Laboratories
>> rickg@centrelab.com
>> USDA 5 or 6 // Sunset 43

While the above regarding sterility is true, there is a difference in the
'sensitivity' (perhaps not the correct word) to mold and fungus between
tissue culture and rooting cuttings.  The medium (agar) that tissue culture
(or orchid seed raising) is done in, is much more prone/conducive to
mold/fungus growth than the medium/atmosphere used in vegetative cuttings.
It is much easier to successfully root cuttings than to 'culture'
vegetative tissue.

True sterility is not always a good thing in rooting (and seed raising)
mediums (unless of course, one is doing *everything* in a sterile
environment, which is not practical in commercial rooting operations).  If
one were to take a 'soilless' mix (sphagnum, vermiculite, perlite), and
autoclave it before use, all sorts of nasty molds and fungi would grow,
most likely killing the vegetative matter, when planted in that medium.
Where as, if the soilless mix is left 'natural' there will (usually) be
very little fungal problems.  We are not talking about TC or raising orchid
spores, we are only talking about relatively gross structures like cuttings
and seeds.

Bill & Harvey
SKID Plants  Zone 6  CT  USA
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