Is tanalised wood safe for veg growing?

Tanalised timber is pressure treated. Unfortunately there is no ticket attached to say what it is treated with, and can even be non-toxic. It might be worth asking B&Q which chemicals they use.

As far as I am concerned, all the timber in my raised beds is pressure treated and hopefully will last 10 years.

I am a pragmatist and as far as I am concerned the amount of chemical that can leach into the soil is minimal and of no danger to human beings at the levels that may be found.

I do not use chemical sprays and use only compost and horse manure. I have even stopped using Miracle Gro as it is unnecessary.

allaboutallotments_Deep_bed_building

B&Q have been selling decking for £3.00 recently, that is £9.00 for an 8ft x 4ft bed that costs £45.00 in the Harrod catalogue that fell out GYO that I bought today.
Even with the coach bolts the homemade bed is less than 1/4 of the cost of the Harrod bed!

Think it's personal choice, but I wouldn't risk it.

If you do i'd put a plastic liner between the wood and the soil to stop any transfer of the chemicals.

Remember you are the one that going to be eating the crops!

Regards

Neil

Allabout liverpool, I have been using Miraclegrow Organic. What do you see as the problem with it ? Is there something I don't know ?

No, no problem, I have just found that plenty of compost, horse manure and comfrey seems to provide all the feeding I need.

As it is all free, there is no point in buying Miracle Gro!

Yes, but I use it for chillies and peppers in the conservatory. I don't want to cart any horse manure in there

Might try B&Q then, I only need about 20ft.

Thanks.

Red

Tanalith Treatment

"I am a pragmatist and as far as I am concerned the amount of chemical that can leach into the soil is minimal and of no danger to human beings at the levels that may be found."

Hi

Can you tell me the source of your information please? I did hear that a study had been done at Leeds University that showed that Arsenic can leach into the soil for up to a metre around a pressure treated fencepost. That suggests to me that a growing bed made of tanalised timber could leach arsenic into your growing medium to a far higher and more dangerous degree. I'd be very grateful if you can point me somewhere that can assure me that this is not the case. After all, plutonium lies around for thousands of years but arsenic is for ever.

I wrote up a post in the Growing Techniques section of the forum. http://www.growfruitandveg.co.uk/gra...rds_26516.html There is no arsenic in pressurised wood that you buy nowadays.

You'll also find tiny levels of Arsenic in most natural soils.

My bed edges in the garden at home are pressure treated and then painted with Cuprinol Garden Shades in a fetching shade of green. I'm living proof it isn't toxic - it's been there for about 5 years.

LOL, well said Flummery, delighted you're living proof (coz I've recently installed raised beds using tanalised wood and was thinking I was a goner....). Also I've recently planted an almond tree and, looking up its preferred location etc on Google, was surprised to learn almond nuts (and many other nuts) contain traces of arsenic... - it's evidently what gives almond paste on the Christmas cake its special flavour, yikes! Further searching provided the usual contrary opinions, one source saying it was a non-toxic form of arsenic, another that if you ate 500 fresh almonds you'd be dead (from arsenic poisoning rather than indigestion...). Arsenic, it seems, in different forms is a very common element - see
Mass Spectrometry - Base Peak - The web's leading Mass Spectrometry Resource
Evidently significant concentrations of arsenic are usually to be found in seaweed which we tend to think is ultra "good stuff"... Uh oh, it's a dangerous life, int'it? b.

Arsenic in soil is nothing. We took some soil samples from South London and when we extruded them for analysis we had pure cyanide running down the side of the soil samples.



Hmm - nice.

We were 'allowed' latex gloves after that.

I can't quote sources at you but I did research this last year for myself and I came to the same conclusion, that the danger is minimal. I am not sure how much arsenic would leak out of the timber if it was treated with arsenic but I am sure that new pressure treated timber does NOT contain arsenic anyway, it was banned throughout the EU a few years ago - at least for domestic rather than industrial use. If you are buying it new from B&Q it will be fine. Old stuff you found on a building site might be a different question.

Here is a thread where it was discussed last year: http://www.growfruitandveg.co.uk/gra...ber_16071.html

Oh - and here are the regulations banning arsenic treated wood from the shelves of B&Q: http://www.opsi.gov.uk/si/si2006/20063311.htm

Tanalised Wood... let me help.

I had raised beds in SW France for many years and went through the same discussions as above at the time about safety.

At the time I was reassured that French stud breeders use tanalized wood in their paddock fences. Now if there was a risk to prize stud horses I doubt they would be using it. They said the horses can lick the fences and there is no problem as the product is irreveribly bound to the wood.

The tanalizing compound contains two key elements: copper and arsenic. The copper, that gives the wood the greenish tint, is there to irreversibly bind the arsenic to the lignin (the natural component of wood). Copper itself is also antimicrobial, Bordeaux mixture (copper sulphate) being used for disease control for grape vines, and of course the arsenic is a potent poison.

Wood can be treated in one of two ways with the above chemical product at the timber treatment yard. Tanalizing can be either by simply dipping the wood in a vat of the product (this is only a superficial treatment - if you cut the ends you'll need to treat the wood at cut ends). For wood that is in constant contact with wet conditions, e.g. bases of fence posts, raised bed borders you will need pressure treated timber for it to last. Here the wood is put in a vat, the air removed from the wood under vacuum, and the chemical then gets sucked into the wood under low pressure. Obviously tanalized wood that is pressure treated will have the product penetrating to depth into the wood and so wood will be more rot-resistant. Pressure treated timber has slightly less mechanical strength than 'dipped timber' but that wont make any differences for fences and raised bed borders, though it might for roof construction. For roof construction the more superficially treated (dipped) wood is used.

I know a little about the above as I worked for the French Forestry Department for several years.

Hope this helps.