Pressure Treated Timber.

[aob9]

 I know this a recuuring subject for some gardeners but it is a disturbing discovery for me. Last year I spent a lot of time and money setting up our kitchen garden. We live in a rural area with lots of four legged friends so I had to build an enclosed area with treated posts and chicken wire. I also decided to build raised beds because our soil is type is heavy clay and very badly drained. The fruits of my labour paid off with a stunning variety of home grown fruit and veg last autumn. I believe in organic growing in principle but I will use an approved pesticide as a last resort if I find I am losing battle with a particular pest. This leads me to my dilemna...I USED PRESSURE TREATED TIMBER FOR MY RAISED BEDS.
It was only yesterday when reading 'Kitchen Garden' magazine I discovered that this type of timber raises health issues due to leaching. So,I did a search on the 'net to find that this is a very emotive subject. Some say it is a load of rubbish, others say that leaching is minimal and local to the timber, others state that this timber should never be near fruit and vegetables. I am particularly concerned as some of my beds are fairly small and will become 'chemical sumps' if leaching really is a problem. To complicate things even further I discovered that the real problem was arsenic used in 'old' treatments and that this has now been withdrawn leaving us with modern 'SAFER'  treatments. .........I have spent some time looking back on previous issues of gardening magazines to find the pages full of raised beds that appear to be built with pressure treated timber. So what is going on here, are all of these experienced and proffesional gardeners( including Alan Titchmark )poisoning themselves and their loved ones or is this debate taking organic growing to extremism.

One final thought, one of the recomended alternatives to pressure treated timber is naturally rot resistant timber such as cedar. Well, guess what?, a study I found on the 'net claims that cedar wood has natural protectant properties that, wait for it; can be harmful to health'.

[aob9]

[Robert_Brenchley]

Anything that 'protects' timber always does so by killing off fungi and boring insects, no matter whether it's natural or artificial. Cedar has long been used for beehives, without any known effects on bees or honey at all. I don't know what effect pressure-treated timber is likely to have, if any, but long lasting timber will never be completely free of poisons!

[aob9]

I have confirmed with my supplier that the timber I used is not the CCA treated timber that was used up to a few years ago. It is pressure treated using the new ACQ method ( better known in the industry as Tanalith E). Therfore it is Arsenic free. Some comfort there but it still contains copper compounds. !!!!!!!!!????????

[Melbourne12]

.......I USED PRESSURE TREATED TIMBER FOR MY RAISED BEDS.
.... is this debate taking organic growing to extremism.
....

We’re not all that organic on our lottie, and will cheerfully use things like metaldehyde slug pellets, artificial fertilisers, and, indeed, tanalised timber.  But whatever you do, there’ll be an organic Nazi looking over your shoulder and pursing their lips, because even if you irrigate your plants with natural spring water bottled in returnable glass, they’ll take exception to the glue used to stick the labels on the bottles.

The real question is, are you happy to eat the produce?  The Expert Group on Vitamins and Minerals recently reported on copper.  I quote:

Occurrence in food, food supplements and medicines
Food
4. Food is the major source of copper intake; in particular, shellfish and organ meats provide rich sources of copper, but drinking water can make an important contribution in some circumstances (paragraphs 11-13). Copper complexes of chlorophyll and chlorophyllin are permitted food colours. The copper content of a number of foods is given in Table 1 overleaf (MAFF, 1997). Copper concentrations in foods may vary widely between countries due to growing conditions, e.g. copper containing fertilizers and fungicides, and type of processing (IPCS, 1999).

Table 1 Mean concentration of copper in a number of foods (MAFF, 1997)
Food Group Mean copper concentration (mg/kg fresh weight)
Bread 1.6
Misc. cereals 1.8
Carcase meat 1.4
Offal 40
Meat products 1.5
Poultry 0.73
Fish 1.1
Oils and fats 0.05
Eggs 0.59
Sugars and preserves 1.5
Green vegetables 0.84
Potatoes 1.3
Other vegetables 0.91
Canned vegetables 1.5
Fresh fruit 0.94
Fruit products 0.73
Beverages 0.1
Milk 0.05
Dairy produce 0.45
Nuts 8.5

Recommended amounts
14. The estimated average daily intake of copper from the UK Total Diet Studies is just under 1.2 mg (MAFF, 1997), or 0.02 mg/kg bw for a 60 kg adult. COMA has set a Reference Nutrient Intake (RNI) for adults of 1.2 mg/day for copper (DH, 1991).

So I don't have any fear of copper poisoning from my raised beds.  Indeed, some health food supplements actually feature copper!

[Tee Gee]

I look upon it this way the human body is a marvellous thing and can cope with most things and more often or not get rid of some of the nasties we come in to  contact within our lives.

Plants!! an other 'living' organism also have inbuilt inhibitors/protectors so to my mind if the plant survives and looks healthy then that is good enough for me! If it dies because of such things then what is the problem it didn't get to the eating stage.

Diversing I watched a programme on 'Global Warming' and saw another slant on the issue.

As I understood it the ozone layer is there to protect us and all the greenhouse gases and smut that is in the air is damaging it, causing global warming!

Well the latest tests taken over America on the three days after 9/11 when no planes were flying proved how much they (planes) pollute the skies.

Well it would appear these scientists have found another anomaly and that is; if we remove (reduce) all these pollutants in the skies this will speed up global warming because the polutants (known as global dimming) are protecting us ??? ???

What happened over the three days was that average temperatures rose 3*C and this was put down to the clean atmosphere ::) ???

So what and who do we believe ? the mind boggles!

I don't want to sound complacent but It seems to me that there are too many people with time on their hands throwing up all those prophecies.

I would say that something is happening but I have faith in nature and think it will all come out right in the end!!

I'll get off my soapbox now because I am beginning to sound like one of those people I have just described!! 8)

[aob9]

I have decided to end my research on this particular subject by opting to keep my pressure treated timbers in situ. The modern material used to pressure treat timber for personal use ( Tanalith E ) consists of elemental Copper and a fungicide called Tebuconazole. Apparently, this fungicide is widely used in cereal production. So, if it's good enough for my bread and beer it will have to be good enough for my garden.

On a side note, I have just watched a documentary on Channel 4 arguing that global warming is a load of rubbish. Respected scientists were in a queue to dismiss the whole idea as absurd...........who do you believe any more?

[Si]

I would not worry about copper compounds or arsenic entering the soil because soil contains vast quantities of these elements anyway. They are normally locked in the soil by bonding to various minerals and are only released when the pH, for example, is drastically changed. Plants can often regulate their uptake of such elements and the only danger to humans is through direct ingestion of the soil itself. Sheep have been poisoned in Wales through ingesting soil! I would advise caution to anyone planning to burn arsenic treated timbers because there have been several cases of poisoning through inhalation of the smoke.

Like Cedar, everything has some level of toxicity... Tea is radioactive (potassium isotopes), orange juice is carcinogenic (causes cancer) and fish is full of mercury.

I wonder whether horses that have been fed antibiotics produce manure that is not organic and bad for soil microbiology?

How organic are raised beds and chicken wire anyway? Surely these prevent birds, invertebrates and other wildlife from reaching the soil?


Tee Gee: Just so that you know... The hole in the ozone layer is a separate problem caused by CFCs and other compounds removing ozone gas. Whereas global warming is the build-up of greenhouse gases such as carbon dioxide and water vapour that traps heat close to the Earth.

[Tee Gee]

Thanks for that piece of info Si appreciated!!

I watched that channel 4 programme last night as well and really enjoyed it! As AOB asked who do we believe? my vote goes to last nights crowd and the previous programme I watched on global dimming.

At least these people have come forward and said their piece against it!! but as yet no one has come forward with  similar detail against it.

Oddly enough I saw a corralatation between the two programmes I have watched which is the reason my vote goes the way it does!

When we were told that adding up all the Co2 emissions formed by mankind adds up to 0.05% of the total gases in the atmosphere yet the total flatulation (farts) from cows is much more the mind boggled.

Add to that that rotting leaves throw out more Co2 than us yet we are advised to compost our greens. ::) ???

Like you say AOB ....who do we believe???

[Si]

I must admit, I tend to agree with you Tee Gee... We are only buying ourselves time because with or without man, global warming is going to heat the Earth naturally. For instance, if the UK stopped burning greenhouse gases now, that would only buy us 5 years over the next hundred before the temperature reached that peak anyway. Assuming the world stops producing greenhouse gases... we will still see a 1.4 degree Celsius rise between 1990 and 2100.

Add to that that rotting leaves throw out more Co2 than us yet we are advised to compost our greens.

The plants absorb back this carbon when it gets into the atmosphere through photosynthesis, so the two cancel out.

[aob9]

Thanks for your contributions to this query, I feel a lot better about keeping my raised beds as they are. The thought of having to rip up my garden was a bit scary.

Anthony

[LJ]

Hi aob9
Hope you don't mind me changing the subject slightly............how high did you build your rasied veggie beds? I've just bought a new house and starting from nothing in the back garden, exciting but scary at the same time!! I too have heavy clay soil but really want to have a go at growing my own veggies and wondered how deep I should make my beds. I'm a new gardener so I'm just going to start with the basics, carrots, peas, beans etc any advice would be greatly appreciated.
Thanks  LJ :)

[manicscousers]

Hiya, lj, welcome to the site, our beds are 12 to 18 inches high but we're working on a waterlogged plot so had to build them higher, I think it's normally about 6" high..have fun  ;D

[LJ]

Thanks for your reply, I can't wait to get started!! Not sure my hubbie is looking forward to building them though!! Another silly question...did you fill your beds with top soil?? I can't believe how different the soil is down here, I'm originally a Yorkshire lass!!

[manicscousers]

depends what your soil's like, you can just skim the turf off and turn the soil to fluff it, we had to fill our beds as the soil under them is so nasty and smelly, and covered in marestail, or horsetail, don't know the difference..covered with cardboard then filled with soil..mix in some well rotted muck, if you can get some, apart from the carrot bed and you can't go far wrong   :)

[LJ]

Thanks  ;)

[Robert_Brenchley]

When we were told that adding up all the Co2 emissions formed by mankind adds up to 0.05% of the total gases in the atmosphere yet the total flatulation (farts) from cows is much more the mind boggled.

If whoever was responsible for this programme was claiming that methane from cows is somehow separate from greenhouse gases produced by humans then they're playing games with statistics. Who, after all, is responsible for the estimated 1.3 billion cattle worldwide?

[aob9]

LJ,
My beds are 6" high except for my raspberries ( 10" 'cos they hate water-logging) and my blueberries ( 10" also, they are set in a special low pH medium). after created the beds I broke up the soil to a depth of about 12" and added some leaf mould and sharp sand. I then added some top soil and rotted manure to the height of the bed. The purpose of all of this was to drastically improve the soil structure from the heavy clay that it was. The good news is that clay soils are generally very fertile.

[roobarbpie]

Hi Aob,
I've also got raised beds made from treated timber.

I recently had a Phd student testing my soil and veg for Arsenic and other toxins. She concluded that they were no problems with either. The arsenic didn't seem to leach into the soil at all. There was a small amount present in the soil (in all parts of the garden) because my garden is an old metal working site, but the veg didn't absorb it.

From her other research on  contaminated sites she concluded that as long as the soil contains all the nutrients the plants require they don't bother to take-up arsenic. ie use plenty of organic matter and you'll be fine.  :)

[LJ]

aob9
Thanks for your advice!! As I said I'm completely new (but VERY excited) to gardening, so any advice is most welcome. What fruit and veg do you think I'm best starting with (i.e. easiest!!).
Thanks again, Lisa

[aob9]

Easy crops would be Radish,Lettuce,Courgette and Onions from sets.New beds are not suitable to root crops such as Carrots as fresh manure can lead to forking. I suggest you start a new thread as the titl e of this thread is misleading for your subject.

BTW 'The Vegetable and Herb Expert' by DG Hessayon ( I think) is a great book for beginners