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topic 45056

Galvanized steel for planting vegetables

A discussion started in 2007 but continuing through 2020


Q. Is galvanized steel safe to use as tomato planters? I am worried about leaching of metals into the vegetables.

Barbara Meserve
hobbyist - Fallston, Maryland


A. Zinc is an essential dietary element.
It is extremely unlikely that any will end up in the tomato but if it does you can put the price up.

geoff smith
Geoff Smith
Hampshire, England


A. Galvanized steel is commonly used for tomato plant towers. Don't process the fruit in galvanized (or bare steel) containers though, as the acidity will dissolve some metal.

Ken Vlach
- Goleta, California

contributor of the year honored Ken for his countless carefully
researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work
which the finishing world continues to benefit from.

May 27, 2009

Q. I bought some large galvanized planters with no drainage holes (for indoor or outdoor use). Since they are square, I am having a hard time finding liners that allow me to maximize the space. I would like to plant some herbs and small tomato plants in them. If I drill holes in the bottom and plant directly in the steel, would the planters be considered food safe for planting?

Linda Gates
consumer - Bethesda, Maryland

June 17, 2009

Q. I use galvanized screen and fencing around my garden. It is buried in the soil, around the plants, to support vines. I also allow my vegetables to sun and dry on a galvanized screen tray. Are there any human health problems associated with vegetables or roots coming in contact with galvanized screen wire? Thanks.

Lance Laton
- Atlanta, Georgia

June 18, 2009

A. Hi, Linda. The earth is largely iron, and zinc is an essential nutrient. There is no safety issue with your plan but, placed in the ground, the planter may rust away to nothing sooner than you expect.

A. Hi, Lance. We relocated your posting to this thread which probably answers it for you. It is safe.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

May 7, 2012 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I'd like to grow an herb garden outside my kitchen door. Crate and Barrel has a "Wide-rimmed planter in lightweight, zinc-finished galvanized steel" with an over-the-railing plant holder that fits over my aluminum railing - very convenient to run out the back door and grab what I need while cooking. And the plants wouldn't take up space on the very tiny patio.

Is there any reason to think that this zinc-finish on galvanized steel could leach toxins into the soil, and then into the herbs? The planter is made in Vietnam. I am somewhat leery of the safety of food related items imported from China or outside the US. If there is the slightest chance of toxicity, I won't use it.

Mary McShane
gardener - Westfield, New Jersey, USA

Galvanized Planter

May 7, 2012

A. Hi Mary.

We appended your inquiry to a similar thread which should help reassure you about galvanized planters. On top of that, your planter is sold as a planter, i.e., it is designed for the purpose, which should offer some indeterminate extra amount of assurance compared to using something that wasn't designed for the purpose.

But with cadmium in children's jewelry that was sold in Wal-Mart, lead in the paint of kids' glasses given away at McDonalds, antifreeze in the dog food ... to require that there not be "the slightest chance of toxicity" is asking way too much. Nobody can promise that ... but I think we can safely say that growing your own herbs & spices in that planter will likely be far safer than using imported herbs :-)


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

May 17, 2013

Q. I have read a lot of answers regarding the safety of galvanized aluminum planters. My question is, what about galvanized aluminum sheets? I saw a raised garden bed on Pinterest made from a wooden frame but on the sides they used galvanized roofing material =>

Would that be just as safe as planters made from galvanized aluminum? I have the same concern that over time the zinc or other metals would leach into the soil. However this would be for a flower garden and not vegetable garden, but the planter would make a nice raised vegetable garden as well...

Roger Ross
- Manchester, Connecticut

May , 2013

A. Hi Roger. There is no such thing as galvanized aluminum. Such sheets are either made of aluminum or they are made of steel dipped into molten zinc (galvanized).

This is just an opinion-based public forum. I don't expect that any epidemiologist will ever conduct a proper double-blind longterm study of vegetables grown in galvanized planters vs. vegetables grown in other containers. But again, zinc is an essential nutrient, not a toxin. And if you are not doing a soil analysis of the dirt that you are planting the vegetables in anyway, nor of the wood that the frame is made of, nor the fertilizers nor plant foods you may be adding, trying to estimate whether there may be a slightly higher zinc level in the soil as a result of using a galvanized planter box seems to me to be focusing on the inconsequential. I'd say concentrate on any insecticide or herbicide use, and that any plant food/fertilizer can be trusted. Good luck.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

June 24, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Hello, I have recently bought some large old galvanised drinking troughs. The idea I have is to fill them with soil and plant them up with edible fruits and vegetables. Should I be concerned about the cadmium and zinc leaking out into the vegetables? I have noticed that the bottom of the inside of these troughs is showing signs of rust so should I be concerned that the coating is breaking down and leaching into the ground also? Is it best to use some sort of liner and what sort do you suggest is the safest to use? Thanking you in advance for your advice. Regards David

david lee
- salisbury wiltshire England

June 25, 2013

A. Hi David. There will be no cadmium is a drinking trough, and the zinc is an essential nutrient.

You may need to be concerned about their durability if they are already rusting though -- so you may want to paint them. But no worries about toxicity. Good luck.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

June 26, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I am trying to find out if there are any long-term issues with growing edible plants in galvanized steel stock tanks or garbage cans. Does galvanization only use zinc in the coating (in which case I don't have much concern) or does galvanization also involve other "heavy" metals, like cadmium? I understand that after several years, the coating will begin to flake off, so I am concerned about uptake into the plants, and hence into the edible parts of the plants. I want to plant in large metal containers to confine the spread of the plants, so it is for long-term perennial use.

Can you compare if pre-galvanized steel or post-galvanized steel would be better for this purpose?

Robert Healey
- Norwich, New York, USA

June 26, 2013

A. Hi. Galvanizing does not use cadmium. There may be small amounts of lead or chrome in galvanizing, or even cadmium, but everything is relative, and galvanized containers will be safe to plant in. Post-galvanized are probably heavier and therefore longer lasting.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

Galvanized Sheet and Composting Rack

April 22, 2016 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Dear Sirs, I am interested in building an above-ground composting rack. One component will be corrugated galvanized sheet metal. Eventually this material will rust. In your best available opinion will the leaching metals be concentrated enough to be harmful. I know that is a broad question, but simply looking for some general guidance. Thanks in advance for your help. Scott

Scott Steinbach
- Waco, Texas

April 2016

A. Hi Scott. No.


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

March 2, 2018

Q. I saw an ad for a space saver strawberry garden. It is made of 3 stacked rings made of corrugated aluminum bands. Is it safe to plant vegetables in aluminum containers?

Linda Griffiths
Home gardener - NORTON, Ohio United States of America

March 2018

A. Hi Linda. There may already be far more aluminum in the soil in the strawberry garden than could dissolve from those bands in a lifetime. Aluminum is over 8% of the earth's crust, and the 3rd most abundant element on earth.


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

March 3, 2018

thumbs up sign  Thank you very much for answering my question

Linda Griffiths [returning]
Home gardener - NORTON,Ohio United States of America

April 10, 2018

Q. Hi! I am planning on using galvanized mesh cloth to line my raised beds. It is steel galvanized post-weld.
Should I be concerned at all about metals leeching into my soil over time? I understand that acidic soil may leach the zinc. Would it be able to leach toxic levels? And I'm worried that the weld is lead based. Is that a possibility? And if so, does the galvanization process seal it in? Would I need to be worried about lead leaching over time as the galvanization degrades?
Or I guess, what would be your suggestion of what to look for in gardening mesh that will be underground to control gophers in a veggie garden.
Thank you!

Jenny Ladd
- Atlanta, Georgia USA

April 2018

A. Hi Jenny. I don't really understand your question about lead-based welds. To my knowledge steel is welded with steel welding rod.

What I would look for is any product designed for the purpose. The chance of you being harmed by it then is quite small; it is when we re-use things that were designed for other purposes that we must worry about what they might be made of. But even galvanized wire cloth may not last more than a couple of seasons underground.


The zinc "leaching" question has already been answered many times already on this page; if you are not confident about internet opinions you can obtain white papers on the subject =>

Luck and Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

August 29, 2018

Q. Hi there,

Instead of using hardware mesh on the floor of my raised bed to keep out voles I want to use painted aluminum soffits with holes. I believe they will last much longer than galvanized hardware mesh. These soffits (2-3) feet are at many construction sites I have seen are for the junk yard.

Is there any issues with the aluminum or the paint poisoning the soil?

frank zaman
- rossland, bc, Canada

August 2018

A. Hi Frank. Aluminum per se is probably not dangerous to plants, as much of the earth is aluminum. However, soluble (dissolved) aluminum is more problematic and quick googling reveals that it can be a serious strain on plants if the pH is under 5.

Hundreds of papers have been written about the subject of aluminum in plants, and I've spent no time with them, so I suggest that you invest an hour or so in research on the topic before committing to this plan.

Paints are of many different types so it's hard to say what is dangerous in the soil. Some consumers would be leery of, for example, the fluorinated paints that are commonly used on industrial and commercial buildings.

Personally, I think you're better off with the galvanized hardware cloth.


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Aloha -- an idea worth spreading

Lead leaching from galvanised steel raised bed?

June 27, 2020

Q. Hi,

Need to build a raised bed because I've discovered our soil has ~150 ppm lead.

Thought about using Galvanised Corrugated Steel, like this:


Now I've learned that Galvanised Steel may also contain lead.
A 3M swab on the panels I bought eventually turns a very dark red. No pink.
Another brand swab is negative.

How much lead is likely to leach from these panels into the soil?



Tom Jones
- San Pedro, California, USA

June 28, 2020

A. Hi Tom
It is extremely unlikely that any lead in a galvanised sheet could migrate ino soil and then into plants which take up very little lead anyway.
But before you rush ahead it would be worth reading
I should also point out that getting a representative sample of soil is not simple. You need a large number of samples from all over the plot from a reasonable depth Mix them thoroughly (not easy) and then halve the sample, halve that and so on until you have a small enough sample to test. Otherwise you might take a single surface sample with one flake of old paint and draw wrong conclusions.

geoff smith
Geoff Smith
Hampshire, England

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