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  • From: "Pete Mattli" <pmattli AT cfl.rr.com>
  • To: "Market Farming" <market-farming AT lists.ibiblio.org>
  • Subject: Re: [Market-farming] treated wood in greenhouse
  • Date: Tue, 17 Jan 2006 01:33:18 -0500

Liz. Allan.  -
Best if you can get the greenhouse tables (GT's) approved by the Organic Certifier (once you
locate one). To do this I would:
1. cover the table tops with a waterproof or water repellant oil cloth type material, stretched tight and
securely tacked down along the edges.
2. Schedule the Organic Certifier's visit with the main pupose of getting some other facet of your operation
approved, making the question of the GT's only incidental to the main pupose of the visit. Mention, but do not emphasize, the ten year old pressure treatment. Ask the certifier if he has any recommendations for your
operation, and say no more. Let the chips fall where they may.
 
Alternatively, replace the GT's with new, untreated wood and double spray the new wood with a highly effective but completely innocuous water-based solution of disodium octaborate tetrahydrate (d-o-t) which
is produced by disolving boric acid and borax in water heated to 180 degrees fahrenheit (100 degrees C.)
to obtain a supersaturated solution of d-o-t. Boric Acid is acidic and borax is alkaline. The resulting solution has a neutral pH of 7.
 
In terms of safety, boric acid has no mutagenic effects, has not been shown to cause cancer, and is non-allergenic. Boric acid has a very low level of toxicity to mammals, and the minimal concentrations used for
wood treatment would not cause the type of problems associated with so many of the other wood treating
protocols. Boric acid itself is commonly used in medicine, even as an eyewash. Boric acid is not absorbed through intact skin. D-o-t is a non-volatile inorganic salt having many of the characteristics of sodium chloride (common table salt). Inhalation is not likely to be a problem. [ EPA Reg. No. 1624-39 & EPA Est. 006574-KY-001 apply]
 
This information says a lot about the safety of borax, boric acid and the borate compound d-o-t, trade name Tim-or.
Tim-or is effective against decay fungi, including brown, white and wet rots, and wood-boring insects such as termites, beetles, capenter ants, etc
[Source: The IPM Practitioner, Volume XXI, #7, July, 1999.)
 
The standard wood treatment using d-o-t is two surface sprayings one week apart using any of the two-gallon garden sprayers. D-o-t is available from epestcontrol.com (website: <www.epestsupply.com>). It comes in a 25 lb
pail costing $89.95. The product, trade named Timbor, mixes 1 lb to a gallon of water. The resulting mix from a
25 lb pail of the powder treats approximately 5,000 sq ft of surface area.
 
Pete Mattli
3805 Scarborough Court
Clermont, FL 34711-6982
ph: 352-536-9586
pmattli AT cfl.rr.com
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----- Original Message -----
From: "Allan Balliett" <igg AT igg.com>
To: "Market Farming" <market-farming AT lists.ibiblio.org>
Sent: Monday, January 16, 2006 10:42 PM
Subject: Re: [Market-farming] treated wood in greenhouse

> >I've searched for this answer and gotten mixed results--seems to
>>depend on which certifier one uses.  The greenhouse tables are
>>constructed with treated lumber.  The tables are about 10 years+ old
>>& covered with wire on which the nursery trays sit--starndard
>>greenhouse set-up.  Is this enough distance from an organic
>>certifier's viewpoint?? Or will they want the wood replaced, covered
>>up, etc, etc?? (I'm still trying to figure out who certifies in this
>>area, got a couple of leads, but no responses to phone calls yet.)
>
> Liz - You certifier my differ, but for DEMETER certification,
> pressure treated wood inside the hoophouse is not going to be
> accepted. old or new. (As Far As I Understand It.)
>
>>
>>Also, most of our pasture posts are locust but a few have been
>>replaced with treated lumber.  There are none within about 200 feet
>>of possible growing space, and like the greenhouse tables they're 10
>>yrs old+.  Will we need to replace these or adjust a buffer zone??
>
> This would fly with Demeter, except, I believe, that any new posts,
> other than corner posts, could not be arsenic-style treated posts (no
> one seems to be willing to 'approve' the EPA-approved pressure
> treated wood, which, I believe, is what you get if you by a 6x6 at
> Lowe's nowadays. This stuff, one would assume, is 'ok' for
> certifiers.) Corner posts, even new corner posts, under Demeter,
> could be even arsenic treated. I assume there is a "30ft from the
> growing area" stipulation to that, but, gosh, it's pretty easy to
> have your corner posts 30ft from a bed.
>
> To digress:
>
> Here in the mid-atlantic, locust is dying out, affected by a heart
> wood fungus, which, if it hasn't prematurely killed the tree,
> essentially destroys all of it's traditional 'rot proof'
> characteristics.
>
> Mark Purdey, of BSE fame, will be speaking at PASA this year. I'm
> sure he'll talk about the changes contaminated rain is bringing to
> soil, drastically affecting the nutrient uptake of native and
> cultivated plants.
>
> -Allan Balliett
>
>
>>
>>& thanks for all the earlie r responses!
>
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