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Re: Addition: Chlorine Bleach (and Peroxide)

  • Subject: Re: Addition: Chlorine Bleach (and Peroxide)
  • From: Alektra@aol.com
  • Date: Sun, 16 Dec 2001 16:08:44 -0600 (CST)

Nothing I have so far read about sodium hypochlorite, on this list or 
elsewhere, suggests that anyone has ever found it inappropriate to use for 
plants. I am going to go into more detail on my reasons for bringing up the 
question in the first place.

Again, I repeat: Chlorine compounds such as sodium hypochlorite, calcium 
hypochlorite, and NaDCC are precisely what tissue culturists use to clean 
leaf-cuts and seeds. In fact, sodium dichloroisocyanurate can be used mixed 
into the medium, right into the substrate, to discourage microbial growth and 
safeguard the plant tissue!

These people do not seem to find a raised final pH to be a problem. For the 
professionals among them, often there's a lot of money riding on the 
culturing. And naturally, people who culture tissue for a hobby would start 
demanding other disinfectants if they didn't like the results they get. If I 
were using one of these chlorine compounds on a rhizome or cutting or seed to 
plant or culture, I would rinse it afterwards, anyway.

Maybe one of you out there who is culturing tissue at home could comment on 
this, or could ask the people on the various home tissue culturing lists, or 
at kitchenculturekit.com. I would think that those of you who are doing all 
that home tissue culturing to build up the santa-leopoldina species would 
know about this.

Cost and availability are serious issues, I think. It is virtually impossible 
to get specific plant microbicides in small quantities at a reasonable cost. 
Specific plant microbicides are hard to get, impossible to mail order, and 
sold in expensive bottles or boxes that are enormous in relation to the size 
of a single dose.

I get awfully skittish at the idea of, hypothetically, spending a work day 
taking a train out to the country to a farm store so I can spend twenty bucks 
on a liter of something just to get 5 or 10 ml, or a pound to get a fraction 
of an ounce.

Furthermore, safety and disposal are even more serious issues. Supposing I 
got a quart of some specific plant microbicide and used the 5 or 10 ml I 
needed, I'd really hate to have the bottle around my place just getting stale 
and waiting to break, perhaps from an accident, perhaps from degeneration and 
pressure inside.

But if I've got a quart of fungicide I need to get rid of, I can't flush it 
down the toilet the way I can with a quart of bleach or other chlorine 
compound. And if there were an accidental swallowing or eyesplash, I would 
=much= rather deal with nontoxic bleach (needing rinsing-- lavage-- and rest) 
than a specific microbicide (intravenous treatments).

Speaking of toilet cleaning, I do not know about the educational background 
of this group, but I thought everybody knows not to mix vinegar, ammonia, or 
other acids with bleach. And nobody I am aware of has suggested vinegar or 
ammonia on plants anyway. There are lots of potentially dangerous chemicals 
that are commonly used at home, and I sincerely think bleach is a lot safer 
than, for example, old-fashioned brown Lysol, or TSP (trisodium phosphate), 
or even Tylenol. There's a certain amount of careful common sense that I 
think that we aroiders share.

Sodium hypochlorite solution, at bleach concentrations or lower, does not 
oxidize one's epidermis when one leaves it in contact with the skin. The 
stratum corneum is a highly effective protective barrier. The lingering smell 
on the skin is not a sign of reaction with the epidermis. It is a sign that 
the stratum corneum has effectively blocked the bleach from going further.

Speaking of aesthetic considerations such as smell, this really is a personal 
matter, insofar as some people actually don't mind it, go swimming in 
chlorine solutions daily, or put their private parts over toilet bowls that 
have water disinfected by chlorine tablets. Calcium hypochlorite and sodium 
dichloroisocyanurate are common pool compounds, and Chlorox sells tablets 
that are put into toilet tanks for slow release.

And speaking of water, one last note about pH, especially, pH 10. My favorite 
bottled water, trinitysprings.com, has a pH of 9.6, and it tastes great. I h
ave a cousin living out near that spring, and he doesn't have problems 
watering his lawn with this 9.6 water. Even four times as alkaline, pH 10, 
we're still not talking about the kind of alkalinity which would dissolve 
pieces of plants.

So, to bring this topic back to where it started, is there anybody out there 
who can comment, from experience, on disinfecting rhizomes etc by using 
dilute solutions of various simple chlorine compounds?

In a message dated 12/13/1 3:46:18 PM, Ted.Held@hstna.com writes:
<< Oops. And when bleach breaks down there is also some residual alkali
(sodium hydroxide, caustic soda) left over. This means the pH will be basic
(probably 10 or thereabouts).
----- Forwarded by Ted Held/PA/Henkel Americas on 12/13/01 09:36 AM -----
                    Ted Held                                                  
                                         To:     aroid-l@mobot.org            
                    12/13/01 08:29       cc:                                  
                    AM                   Fax to:                              
                                         Subject:     Chlorine Bleach (and 
                                         (Document link: Ted Held)            

Here are a few comments about chlorine bleach (sodium hypochlorite):


Relatively non poisonous - provided you don't acidify it (as by adding
vinegar), which will release actual chlorine gas, a decidely toxic
material. See later comments.

-Compared to complex organics, less persistent

True. But many of the commercial microbicides are actually not very
persistent as was the case with early pesticides. I think current
microbicides are good when used as directed.

-Not absorbed by tissues (the prize plant or our skin and lungs)

Will be absorbed by tissues as you might notice if you use bleach without
gloves. That offensive (to me) smell that hangs on your exposed skin is
evidence of lingering chlorine absorption (and tissue degradation).

-Breaks down into water and ordinary salt

Yes, once its oxidizing work is complete.

-Even cheaper than hydrogen peroxide

Pound for pound, bleach is less expensive than peroxide as a microbicide.
On the other hand, we in the hobby are not in the business of mass killing
where the cost is really a factor. Bleach happens to be handy, however,
meaning that you have a disinfectant in the house whenever you need it.

-Does not oxidize living tissue

Does, in fact, oxidize living tissue. That is the way it kills. Bacteria
and fungi are oxidized to death. It will oxidize your epidermis if not
protected. Not advisable to leave it in contact with skin for any length of

-As for friendly microorganisms, they can repopulate the sanitized areas
rapidly by spreading from the healthy surface of a tuber, or from healthy

True, provided the residual bleach is rinsed away and a healthy inoculate
is available.

-Very low concentrations will kill germs

True. Bleach probably has ten times the killing power compared with an
equivalent of peroxide. Incidently, will increase its killing power
dramatically if the pH is lowered, making chlorine poison gas more readily
available. Acidification by non-professionals is not advised.

-You don't have to wear a respirator or chase away the kids and pets.

Some people don't like the smell of bleach. I find it cloying and choking
when used in a confined space. If you make a little dilution in a bucket
for washing off tubers all you really need is a modicum of air circulation.
If you acidify it, chlorine gas is really gross and can actually kill you.
Take my word for it. >>

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