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 _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/… Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net> PBS Forum https://…