permaculture

[FionaNyx <FionaNyx@aol.com>]

steved@ncatark.uark.edu wrote:

I've caught a few itsy bitsy pieces of scattered information about
the use of concentrated vinegar for vegetation control.  <snip>
Questions: 

1.  What is 9% vinegar, how does it compare to regular apple cider
vinegar available in natural food stores, or to supermarket brand vinegar? 

F:  Regular vinegar (both apple cider and distilled white) is typically
diluted to 5% acidity.  

2.  Where can you buy 9% vinegar?  Can you purchase it locally
if you know what you're looking for, or do you have to obtain it via
mail order from a certain supplier? 

F: Stronger vinegars are available from well-stocked groceries (at least in
the Philadelphia area) for the purposes of pickling (you add the vinegar to
veggies-- you want the final combined pickle to be at 5% acidty (for
suppression of bacterial growth).  Acid percentage is listed on vinegar
labels.  

3.  Do you spray it straight, un-diluted?  

F: I'm assuming 9% vinegar means spray it straight. 

I'd guess that would limit the area you can economically spray.  Or, maybe
low-grade types of
vinegar can be purchased in 55-gallon barrels at cheap costs?

F:  This is purely theory on my part, but it seems to me that since vinegar is
DILUTED to 5% acidity, one could therefore CONCENTRATE it back UP the acidity
scale.  Presumedly you can get from 5% acidity to 10% acidity by removing half
the volume of water through either boiling or evaporation.  Any chemists care
to speak up here?  We know (again from pickling) that boiling does not destroy
the acid content of vinegar.  

Vinegar for industrial food production (think Heinz pickles) must exist and is
probably far less expensive than cheap grocery vinegar-- but how to get just
one barrel of it (and is it shipped in barrels)?

Again, you could easily ferment your own vinegar from apple juice or cider--
but the ingredients are probably more costly than just buying the vinegar
which is quite cheap by the gallon.  

Another potential cheap source of vinegar if you have a local winery is
batches of wine gone off.  (You would need to filter it to prevent sprayers
from clogging.)  A problem with this supply is that it is unreliably
available.

This brings me to mention citric acid which is sold in the powdered form as a
brewing supply to use in adjusting the acidity level of wines.  Homebrew
supply houses carry it and a phone call to one will tell you how much you need
to make a gallon of water 9% acid, and what quantities they offer at what
prices.  While not organic, it's a darn sight better than glycosulphate
(Roundup).

4. How effective is this practice?  Under what conditions does
it work well and which plants are controlled better than other
plants?  

F:  I can't answer this.

5. The Kerr Center in Poteau, OK, tried the vinegar spray approach and 
reported that the vinegar ate the sprayer; thus, the expense of replacing 
equipment parts off-set the advantages.  Any info available on suitable 
spraying equipment? 

I have a plastic pump sprayer.  I think these are available for the gallon
size.  This would seem to be the way to go.

I know these are technical questions but I'd really like to find out more 
about this practice so the info can be made available to a broader 
audience.  

Thanks! 

Steve Diver


> More seriously, though,
> 
> 9% vinegar sprayed on poison ivy leaves will kill them (especially in
> sunlight and warm weather)... they will come back from the roots, and must
> be repeatedly sprayed. If successive sprayings are made while re-sprouted
> leaves are still small, the roots will starve in a season (if leaves get
> very large, the roots recover quickly and the spraying can go on
> indefinitely).
> Jack

Hope this was helpful,  ~~Sherry