Treated lumber?
 

Just wondering how many of you use treated lumber for your raised beds. I removed my dilapidated greenhouse and am going to add another raised bed. I used treated lumber on my first bed, just curious as to what you guys use.

Duane

This is one of those perennial topics that can be a bit controversial.

Pressure treated wood is treated with an arsenic-like compound.

The questions to consider:
* How much leeches into the ground?
* How much makes its way into your veggies?
* How much longer does it last than regular lumber?

Some of my garden beds are pressure treated, some aren't. It came down to budget for me.

I suppose weed barrier could be used to try to keep some of the chemical seepage out of the soil. Some tests have been done (no, I don't have links), showing that the amount of hazardous chemical that leeches into the vegetables is very low, but I don't blame people for not wanting to take that risk.

Untreated lumber may need to be replaced as often as every 2-3 years.

FYI: Googled this:
" Nearly 40 million lb. of arsenic is used in this country every year, and most of it goes into the pressure-treated wood that we use to build decks and playgrounds. But that all changes Jan. 1, 2004. The Environmental Protection Agency (EPA) is banning chromated copper arsenate (CCA) as a preservative for wood intended for residential use (except for the lumber that is used in permanent wood foundations). CCA-treated lumber will still be available for industrial and agricultural use, however.
By the way, there's no need to panic about existing CCA-treated structures. The EPA says that they're fine. But if you're nervous about the chances of leaching chromium and arsenic, you can make your deck or swing set safer by coating it with an oil-based penetrating stain every couple of years.
Taking CCA's place as a preservative are two waterborne compounds: alkaline copper quat (ACQ types B and D) and copper azole (CBA-A, CA-B). Sold under the trade names Preserve, NatureWood, and Natural Select, they have been used around the world for up to 15 years. These EPA-approved low-toxicity pesticides resist bugs, mold, and rot as effectively as CCA. (See How much safer? for more on quat and azoles.)"

dcarch

Glad you guys posted this as I was going to use the wooden "kiddie" playground set when I take it down this spring for raised beds ,,,
I wonder if its old enough for it not ot matter ?

I'm strickly organic so ... prob. wouldnt want to take that chance ~

Tom

Acq is what everyone carries locally.

[quote=Tomstrees;52894]-----I was going to use the wooden "kiddie" playground set when I take it down this spring -----------
Tom[/quote]

Don't.
You may need the Kiddie playground set sooner then you think.:arrow: :lol:

dcarch

I buy what they call green wood. It is 4" by 6" by 8' and it seems to last very well. I built more first 9 raised beds out of it 4 years ago and it is still looking real good with no rot at least on outside...only thing leaching from the "green wood' is sticky sap...
Those boards make some nice hefty, sturdy raised beds..I have...$12 for each board so it does add up but I love em...

Keith

4" x 6" wow that's thick.

Think I'll run right out and buy some YellaWood (What they are calling it here) with confidence. ;)

Why not use broken up concrete? Anytime that
I browse Craig's List, I see it available for free.
One can mortar manageably sized chunks of it
together with type-S mortar ($5 for a good-sized
bag at HD). It requires some exertion and
muscle to hand-mix the mortar in a bucket,
but the wall will not rot, is not toxic (lime,
gypsum, and various kinds of sand and gravel),
and one can make the sides as high as one desires.

One can easily make it higher in successive
years after adding more compost, manure, topsoil
or whatever to a raised bed: simply mortar another
layer of concrete chunks on top of the existing walls.

(People who habitually overbuild will want to
pound 2-3' pieces of rebar into the soil every
4-6' of wall, with 4-6" left sticking up into the
mortar between chunks of concrete in the bottom
layer.)

Wood is light and easy to machine and looks
nice in a yard, but it does rot, especially in
contact with soil. Concrete is heavy and requires
muscle to build with, but it does not need to be
treated with anything to avoid rot. One can
make it a little easier to work with by ignoring
"must take all or nothing" listings and only
selecting chunks that one could easily carry from
the pile of debris to one's vehicle. (Caveat: using
small pieces requires more mortar.)

The caveat with pressure treated wood without the old treatments is that it does seem to be more susceptible to decay. In fact, in our experience in California, pressure treated wood is rapidly losing favor to other materials as it is not a long term solution where soil contact is considered. The process, more so thatn the chemicals seem to be at fault, with deoth of chemical treatment being the biggest issue. In fact, most of the manufacturers no longer warranty the produict for soil contact at all. The key is keeping moisture from building up in contact with the wood. One of the ways we see this being achieved, is by backing the walls with drain rock wrapped in filter fabric to a width of at least 6" and leaving a gap of 1/2" above grade to allow drainage. Also, many advocate that all cut ends be treated with preservative prior to assembly of structures.

BTW, as recently as a year ago, I saw some old stock with CCA tags, there is still some old illegal stock out there. As well as Wolmanized lumber.

Most of our beds are pressure treated wood. I've read that the arsenic leaches only a very short horizontal distance. In the veggie beds we dug out a few inches of soil, added a non-pressure-treated liner, and filled it back up. Probably not necessary, but I feel better.

I have a pressure treated fence and have often wondered about it, but I have been reassured multiple times that its ok.

Dcarch ~

HA HA !!! LOL ~ wait a minute..:shock: ...you might be onto something here! :mrgreen:

~ Tom

I agree with John; if you look at the labels on pressure treated wood most manufacturers now stress the fact there is no arsenic in the chemical treatment process.

PS: If concerned about appearance with an ad hoc,
recycled material in a mortared wall around a raised
bed, one can plant evergreen huckleberries (or
whatever appropriately sized low shrub or other
evergreen plant will stay healthy with low
maintenance in a particular climate) around the
outside of it. Good place to grow some heat-loving
herbs, for example.

Treated wood
 

I looked into this a few years ago and after extensive reading. I have concluded.
1. even if using older treaded lumber Arsenic is not take up by plant roots.
2. I would be very careful not to breath the saw dust and remove any generated during building. Arsenic and copper sulfate and the other verious form of copper they tread wood with are not good for you.
3. Untread lumber is cheaper and if paint with tung oil (or paint which is more expensive) it last a long time. Seven years to date and holding the beds in place with little sign of decay. (And that is in the hot sometimes wet south)
Celtic

[FONT=Arial][SIZE=3][COLOR=black]I don't know if this is true:[/COLOR][/SIZE][/FONT]

[FONT=Arial][SIZE=3][COLOR=black]I seem to remember that they used to burn (char) the ends of poles before bury the poles in soil. [/COLOR][/SIZE][/FONT]

[FONT=Arial][SIZE=3][COLOR=black]The carbon coating prevents the wood from decaying.[/COLOR][/SIZE][/FONT]

[COLOR=black][FONT=Times New Roman][FONT=Arial][SIZE=3]dcarch :?:[/SIZE][/FONT] [/FONT][/COLOR]

thats what they do to telephone poles.

If arsenic leaching is an potential issue why not line the part of the wood in the raised bed that is in contact with the soil with thick building/contractors plastic..?

It will aid in moisture retension and also slow down the degradation of treated or untreated wood for that matter. Just a thought.

Red Cedar
 

Use good old west cost red cedar for very long life and now chemi worries.

Around here a 2"x6"x10' treated costs $9.00
A 2"x6"x10' TREX is $54.00
A 2"x6"x10' AZAK is almost $40.00
There are concrete molds available to pour your own 2"x whatever "boards" with fiber mesh and rebar, that would outlast all of them, for a little more than treated lumber.

The new treated lumber used today contains arsenate, instead of arsenic. It is less toxic. It is also highly corrosive to greenhouse plastic. Treated lumber needs to be painted before touching poly.

I read that with the old stuff, root crops grown in pure treated lumber sawdust would get slightly above the government safety threshold, but only on the very tip of the radish or carrot, the part that a person would not eat.

I will be honest I could give a hoot about treated lumber I use it all of the time in my outside projects.
The amount of pollution many people breath in everyday far exceeds anything you will get from treated lumber.
I thought I was going to die when I had to go outside in LA one time.
Landing there looked like we were landing in a BBQ grill but it wasn't BBQ.:(
That's why the rich folks live up in the hills above the haze.:lol:
Worth

Cole, I agree. Paint it.

I wish I had taken pictures of untreated rotten 4" round posts compared to treated 4" posts. One is still usable and the other got termites and then got burned.

I've just used 2x12's. Replaced about half of them over 15yrs. One or two a year is
not a big deal.
The fence posts are 4x4 treated. Beeswax/oil treated the bottom 2 feet.
Paint would be a mess i think. Moisture will quickly get in and start the peeling process
well ahead of wood rot.
I have a wooden boat....very high maintenance.

Beeswax 50/50 oil applied hot will penetrate nicely and harden forming a pretty good
water barrier.

My house is unfinished cedar built '62. My barn is painted and needs it again. Built by us 15yrs ago.

The whole point of my garden, as well as therapy, is fresh clean produce. Rather not count on anyones word as to what is safe. We were crop dusted on the school playground in the 60's with all sorts of chemicals thought safe.

I'm using treated 2x4s ripped into 2x2s for most of my trellising and fence posts. I sharpen one end and drive it with a sledge hammer.

For people on a budget or folks that just want to know or save money there are some options out there that aren't very well advertised.

Lets start with mineral oil.
What is mineral oil yes it is me again talking about the stuff and how much I use it.:lol:
Go to wall-mart tractor supply or any oil distributor and get hydraulic oil.
NOT Hydraulic transmission oil.
Look for an ISO rating like ISO 32 ISO 46 or ISO 68.
The higher the number the thicker it is.
What is it?
Mineral oil, the same stuff used to preserve cutting boards to hone knives with and so on.
Is it food grade no but I can guarantee you it is safe and has little to no taste.
You can get 5 gallons of the stuff at tractor supply for around $30 some odd dollars.
At the same place a gallon is $20 some odd dollars.
Turbine oil is the same thing.
Power steering fluid same thing.
Heat it up and mix your bees wax with it.
The same stuff sold at the store is close to $9 for 12 ounces.:lol:
Amazing what labeling can to to a price.

Worth

Asphalt
 

We have been coating the bottom and insides of raised bed woods with asphalt.It is not water soluble and will not leach.All my bamboo bottoms and tips are coated with Asphalt.Any wood that touches concrete slabs should be coated with a moisture/chemical barrier.

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