Safe or Not

[Nyboy]

I made a big mistake, on how much lumber was needed for a dock. I had 3x what was needed delievered of pressure treated 2 by 6s. I always read never use pressure treated wood for raised beds for vegetables. I read somewhere ( think here) that pressure treated wood is now made diffent and is safe to use. The wood came from home depot only labeled pressure treated on bill. I did notice it doesn't have that green color PT wood use to have. Is it safe for raised vegetable bed? Would you use it?

 

[digitS']

@Nyboy ,

Would you like to see what Cornell Extension has to say?

(LINK) 2 page pdf download

They are saying "DO NOT."

Steve

 

[Ridgerunner]

They used to use arsenic to treat wood. They don't anymore. They still use oil or creosote for some treated wood but from Home Depot that's not what you bought. That's for different purposes. You can always ask Home Depot what the wood was treated with. It won't cost you anything and you might get an answer. They should have the MSDS for it somewhere in their supply chain. You might ask fort the MSDS.

They use different chemicals to treat the wood now. Most of these compounds are based on copper, not arsenic, though there are other things they might use rather than copper based chemicals. These new compounds are not considered nearly as dangerous to us as arsenic.

So would I use this wood in a raised bed? Yes. If you do you will not be considered organic. Any treated wood is against the organic rules but I personally would not worry about it.

Just to stir things up this Monday morning, the danger from arsenic-treated wood was not that the arsenic would leach out of the wood into the soil and cause the stuff you eat to be poisonous. Poison is about dosage and you won't get a bad dosage like that though I don't advocate eating small amounts of poison in any case. That much would not leach out and besides the plant would die before it absorbed enough poison to do you any harm, or even harm kids who are more susceptible. The danger was more from the arsenic leaching to the surface of the wood and concentrating there, then getting on us when we rub against it. It was concentrated and more of a danger, especially to kids that can't keep their hands out of their mouth.

These new chemicals are not supposed to leach as much as the old arsenic ones did and are not as harmful to us to start with. But it is a personal choice. I use pressure treated wood as fence posts around the garden and occasionally sink a treated post in the garden itself to support a trellis. I have one "raised bed" against a block building where the treated wood forms three sides of the bed and I occasionally grow stuff to eat in there. That's about it for my actual use of treated wood around stuff I grow to eat.

Look at it this way. You used it for your dock where you might expose more skin to it than you would in the garden. It wasn't a concern there.

 

[Nyboy]

Steve link didn't work for me. Ridgerunner I am so glad you replied, your great knowledge always impresses me!!! I am not worried about being organic.

 

[Ridgerunner]

That link worked fine for me both times I tried it. I just clicked on it.

Steve, can you find a date on that. Most of the sites I find talk about CCA (that's the one that has inorganic arsenic), but that was phased out voluntarily by industry over ten years ago. In this Purdue article they say the EPA has approved ACQ treated lumber but I think that is a fairly old article too. I can't find anything from a University that I think is current.

http://www.hort.purdue.edu/ext/ho-200.pdf

Steve, you are a better researcher than me. I could not find anything the EPA had to say about anything other than the CCA wood for raised beds. It would be interesting to see what they say about other chemicals, the ones in use today.

 

[Nyboy]

Think it is time for new computer

 

[digitS']

Cornell put the file online last year. You will see that in the url. It was written in 2002 and revised 2 years later (at bottom of page).

I also looked at the U of Georgia extension and they talked about other preservatives and the organic standards, pointing out that natural oils used on wood are not really shown to preserve it when in contact with soil.
Here is UGa (link)

@Nyboy , what I did to use my neighbor's treated wood beds was to empty them and line them with plastic film. That was quick and I was trying to get the bindweed roots out of that soil! Some people won't use plastic and I know it won't last forever but the wood won't either.

In the shady corner of the little veggie garden, the owner used railroad ties along the driveway. I have no idea how old those ties are and simply pull weeds and leave the first 12" to 16" of soil undisturbed. Those ties are pretty nasty and I'd never lay veggies on them or park my derriere on them on a hot afternoon, for that matter.

Steve

 

[digitS']

NyBoy, I had to leave the tablet and go to the PC to copy text easily from the pdf @Ridgerunner linked, even if I could open & read it on the tablet ... there was a stop in the kitchen to stir up the pumpkin pie filling. Was that what @Ridgerunner meant by "to stir things up this Monday morning?" :

"Wood containers should be made of a naturally water-resistant wood (such as redwood or cedar) or synthetic lumber (such as recycled plastic). If using chemically preserved wood, choose lumber that has been pressure treated with a copper-containing product such as alkaline copper quaternary (ACQ). Copper and zinc preservatives that are painted onto the wood are less effective in preventing decay. Do not treat wood with creosote or pentachlorophenol (Penta) because they are potentially toxic to plants, particularly when grown in small, enclosed areas."

Steve
now I'm hungry & those pies aren't even in the oven!

 

[Ridgerunner]

Cornell put the file online last year. You will see that in the url. It was written in 2002 and revised 2 years later (at bottom of page).

December 31, 2003 is when the industry quit using CCA (inorganic arsenic) treated wood. I consider that Cornell article dated.

I also looked at the U of Georgia extension and they talked about other preservatives and the organic standards, pointing out that natural oils used on wood are not really shown to preserve it when in contact with soil.
Here is UGa (link)

This one was published in 2013 so much more relevant. Thanks. The only comment I can find in there about this is Similar concerns have been expressed over pressure-treated wood, though current formulations appear to be safe for food production. USDA Organic Certification guidelines do not allow any of the pressure-treated wood products to come in contact with plants grown for food.

"Appear to be safe for food production" is about as good as you are going to get a government agency to say it is "safe". They are real fond of phrases like "not known to cause harm". If it is known to cause harm they normally are pretty straightforward about that but I can't think of anything where they come out and say something is "safe". It's always possible something can come up in the future so they use weasel words as much as they can.

 

[digitS']

Well, I use weasel words, too.

On another forum, someone asked for a mushroom id. I told myself, "don't even open that thread!"

I recently became somewhat aware (weasel word: "somewhat") that mushroom toxins can cause cumulative damage. I guess I mean (weasel: "guess"), one may not know that he or she has consumed something that caused damage. Continued eating just adds to the tissue damage.

Steve