Is my garden safe to eat from?

[mrdifro]

Hi, a couple years ago I made an in-ground vegetable garden in my backyard, and it's framed with pressure-treated lumber. It wasn't until now that I found out that you're supposed to line the wood with plastic to keep the soil from making contact with the wood, which it already has. Are my vegetables safe to eat? Is the soil no longer usable?

 

[Meadowlark]

Personally, I would not eat veggies grown in it. Part of the purpose of growing veggies for me is being chemical free.

 

[mrdifro]

Personally, I would not eat veggies grown in it. Part of the purpose of growing veggies for me is being chemical free.

Thank you for your response, but I was hoping you or someone could answer in greater detail. Is it really so unsafe that I should be concerned? Is the soil totally unusable now? Should I tear the entire thing down and start again next season in another spot?

Thank you for your time.

 

[Chuck]

There are two types of treated lumber, CCA and ACQ. CCA is copper chromated arsenic and the arsenic does leach into the soil. ACQ treated lumber is made with non-toxic materials. If you bought the lumber from a lumber yard, hardware store, Home Depot, Lowe's etc. it will be either marked or stamped. If the marking or stamp has LP22 or LP2 it is CCA treated. This is extremely unlikely as CCA lumber is normally not sold to the general public.

 

[Mick Emery]

If you bought the pressure treated after 2004 I would say it's ACQ & no need to worry.

 

[YumYum]

To my understanding the greenish tinted telephone poles have the copper in them to give you something to compare to. They have recently put up a few around here.

 

[Chuck]

CCA lumber is still available but it is not on the shelves. Contractors and homeowners can still get it to build decks and patios etc. Landscape timbers can also be obtained and of course the telephone poles. You have to ask for CCA and most times it will be special ordered, at least that is how it is around this part of Texas. It is not banned but it is restricted by the sellers themselves.

 

[NigelJ]

Hi, a couple years ago I made an in-ground vegetable garden in my backyard, and it's framed with pressure-treated lumber. It wasn't until now that I found out that you're supposed to line the wood with plastic to keep the soil from making contact with the wood, which it already has. Are my vegetables safe to eat? Is the soil no longer usable?

Vegetables safe to use? Yes. Soil no longer usable? No.
Although copper, chromium and arsenic are not good for humans, or other animals, they are not going to leach very far into the soil. If they reach the plant roots will they be taken up? Not to any great extent. If taken up will there be sufficient in your veg to harm you? Almost certainly not.

 

[DirtMechanic]

Some heavy metals are nutrients at a certain lower levels and toxic at high levels. Copper and Zinc for example. I use zinc coated metal fencing, and zinc coated tomato and pepper cages, and cucumber trellises. I have 4x4 treated posts supporting perimeter fencing. Here, because Birmingham burned coal for steel, Arsenic is found in the surface of the land and probably therefore mercury too. It is a real concern, but as the paper I am linking suggests, both quantity and type of metal are as important as time of accumulation

Not a fun read, be prepared to look up words.

Accumulation of Heavy Metals in Vegetable Species Planted in Contaminated Soils and the Health Risk Assessment

The objectives of the present study were to investigate heavy metal accumulation in 22 vegetable species and to assess the human health risks of vegetable consumption. Six vegetable types were cultivated on farmland contaminated with heavy metals (Pb, ...

www.ncbi.nlm.nih.gov

 

[Meadowlark]

Excellent article...the conclusion "These results indicated that the low accumulators (melon vegetables) should be suitable for being planted on contaminated soil, while the high accumulators (leafy vegetables) are unsuitable." is interesting and informative but unless one knows the specific levels of contamination and type it's a total guess to answer the Op's questions.

I'm just not in favor of guessing on matters that are critical to human health. Just not worth it. So easy for someone to say it is safe without any knowledge whatsoever of the specific levels and type of contamination.

 

[DirtMechanic]

Excellent article...the conclusion "These results indicated that the low accumulators (melon vegetables) should be suitable for being planted on contaminated soil, while the high accumulators (leafy vegetables) are unsuitable." is interesting and informative but unless one knows the specific levels of contamination and type it's a total guess to answer the Op's questions.

I'm just not in favor of guessing on matters that are critical to human health. Just not worth it. So easy for someone to say it is safe without any knowledge whatsoever of the specific levels and type of contamination.

Toward that end I thought the detailed illumination of testing methods and procedures fortified the ability of someone to even ask a pertinent question of a local lab or resource.

 

[Ruderunner]

Considering how long humans live despite all these toxins around us, I wouldn't worry about it.

You might only make it to 79.5 vs 80