For those who don't know, wear gloves and eyewear when working with Xerotol as it will burn and turn your skin white.
On Friday, September 8, 2023 at 04:42:04 PM CDT, Steve Marak via pbs <pbs@lists.pacificbulbsociety.net> wrote:
Combining some comments on several branches of this thread -
James, my wife has used peroxide in orchid seed flasking. The procedure
was to soak the seed in a sugar solution for some hours to "wake"
baterial/fungal spores, so they're easier to kill, drain, add fresh
peroxide, soak a while, drain the excess liquid, and sow. We've also
used it, on recommendation by a friend who is a commercial orchid
grower, on bacterial/fungal issues with orchids as a drench. It worked
far better than I expected and is now part of our arsenal.
Eric, I've not used Zerotol but I think it has a stabilizer added so
that it doesn't break down so quickly upon opening. I looked at it for
that reason, and because it's has a higher percentage of peroxide than
the pharmacy grade, but we use such small amounts it wasn't cost
effective for us.
Leo, the manufacturer of Physan does say to drain the solution off seeds
and cuttings before planting. I've never tried it myself - like Dylan, I
never try to disinfect cuttings (and seeds only if they're going into
sterile culture). Cuttings get a good soak/rinse to remove dirt and any
pests, then rooting hormone and straight into medium.
Patrick, thanks for reminding me about NaDCC (dichlor)! A friend has
switched to using it in his orchid flasking and like you recommended it
highly. I intended to try it but just forgot.
Steve
On 9/8/2023 1:42 PM, James Frelichowski via pbs wrote:
> I have used peroxide as disinfectant. It evaporated or is broken down by enzymes and you don't need to rinse with sterile water. For hard seeds, if trying to germinate, combine with heat and even a sonicator water bath to get better kill and even eat away some of the seed coat. You can do the same with bleach but it must be diluted another one tenth and only for a few minutes maximum.James FrelichowskiUSDA cotton collection curatorCollege Station, Texas
> On Thursday, September 7, 2023 at 06:36:38 PM CDT, Lee Poulsen via pbs<pbs@lists.pacificbulbsociety.net> wrote:
>
> Just a warning on Physan that I learned the hard way. It’s great for all the uses Steve mentions. But I once thought it would be great to put just a drop in the water that I was floating some older Hippeastrum seeds in, so that I wouldn’t have to change the water in the cup as often, because the chlorine compound they put in the tap water eventually evaporates off and the water has to be changed for longer term germination times that older seeds require. It inhibited the germination completely. I don’t think it killed the seeds; I would see a root tip emerge. But then the root never grew any longer, but didn’t die either. It was as if they were in suspended animation. And changing out the water never helped the seeds begin growing again. The seeds were a total loss.
>
> As for the superior efficacy of Clorox/bleach, back at the beginning of the pandemic, experiments showed that bleach killed the COVID virus fairly quickly, so it’s good even against viruses. Unfortunately, that led to the comment about seeing if there was a way to inject it into the human body to stop the disease and people forgot about the original research results.
>
> --Lee Poulsen
> San Gabriel Valley, California, USA - USDA Zone 10a
> Latitude 34°N, Altitude 340 ft/100 m
>
>> On Sep 7, 2023, at 10:14, Steve Marak via pbs<pbs@lists.pacificbulbsociety.net> wrote:
>>
>> Shmuel,
>>
>> In all the reading I've done, bleach (Sodium hypochlorite solution, Clorox is one trade name) is still the gold standard for disinfection. Cheap and common, it kills pretty much everything, with shorter exposure times required than for other agents.
>>
>> https://pubmed.ncbi.nlm.nih.gov/28722950/
>>
>> I prefer other things because chlorine is so corrosive to skin, nose, lungs, eyes, etc. also to most metals and even many plastics, which become brittle faster if regularly disinfected with bleach. I use quaternary ammonium compounds, e.g. 409 or Physan, to clean hummingbird feeders. The disinfection time is a little longer, but just a few minutes and worth it to me to avoid the bleach. Physan can also be used on cuttings or even as a soil drench to control damping off and other bacteria, fungi, and algae.
>>
>> I do use bleach when cleaning anything I use to prune or divide orchids as a precaution against orchid viruses. Even Physan will not reliably kill those, at least not without soaking longer than I'm willing to wait.
>>
>> Steve
>>
>> On 9/7/2023 11:22 AM, Shmuel Silinsky via pbs wrote:
>>> I wonder. I used to soak aquarium plants in a potassium permanganate
>>> solution to kill unwanted hitchhikers from snails to protistans. I wonder
>>> if this would be effective for cuttings... What is the issue? Does Clorox
>>> help against bacteria, virus, fungi?
>>> Shmuel
>>> Jerusalem Israel
>>> Zone 9b
>>>
>>> On Thu, Aug 24, 2023, 6:10 PM Tim Eck via pbs <
>>> pbs@lists.pacificbulbsociety.net> wrote:
>>>
>>>> I am going to take some cuttings for rooting and I would like to know what
>>>> would be a good concentration of clorox to use to sterilize them without
>>>> damaging them.
>>>> Thanks
>>>> Tim
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