Not poisonous.

Jon

It's fine to use in the garden.

Thanks, how do you all know?

It's just unfinished carbon steel. I am not sure why it would cause any concern. Perhaps someone knows of a reason it's a problem, but I sure don't.

I have used rebar stakes for 3 years to hold up my tomato cages and bean trellises. Never had a problem.

I've used rebar for over 35 years....never had a problem.

Rebar, which is nothing more than plain old steel, has been used by gardeners for years. So a better question would be why would the fact that "someone mentioned to me that it leeches poisonous metals into the soil" suddenly make it's use questionable or hazardous? What was their proof of their claim?

Steel is just an alloy made of iron, carbon, and various other elements like manganese, chromium, vanadium, and tungsten. All of which are normally found in soils to various degrees.

If you aren't comfortable with it then just don't use it.

Dave

Completely safe. It's steel. Iron and carbon mostly. When it oxidizes it produces Iron Oxide ... which is rust! Which is the same ingredient used in "Ironite" or iron supplements that are sold all over the place to supplement your garden, and your lawn. So it seems it may not only be safe, but beneficial to your garden.

Tim

Some people even take their "old rusty nails" and push them into the ground around plants for the slow release iron for their plants. That has been going on for over 50 years.

Thank you very much everyone!

There are usually small amounts of lead, for example, in rebar, as it is produced from recycled fridges, auto parts, etc.

Now another scare?

also cadmium and arsenic. It's just the facts of the science, as 93% of rebar is from recycled scrap metal. There's no way to know the actual composition of what you buy in Home Depot, but it's not pure carbonized steel in any case.

The amount of lead that is going to leach (or corrode) out of rebar is small compared to what you already have in your soil. Especially if you're anywhere near a road. If you're still worried about that, get rid of all your chicken wire and metal mesh. That stuff is also low grade steel. "Unfinished" steel is just steel that hasn't been rolled. Has nothing to do with composition. That being said, iron is a poisonous metal too. Just takes a lot to hurt you.

Thanks. I found this info interesting: https://www.jlconline.com/tools/power-tools/12-things-you-probably-dont-know-about-rebar_o

"There are usually small amounts of lead, for example, in rebar, as it is produced from recycled fridges, auto parts, etc."

"also cadmium and arsenic. It's just the facts of the science"

Could you provide a scientific reference for those metals & their percentages in rebar, or are you just guessing?

Hi Zeedman,

Re the quote you cited: the author is necessarily "just guessing." That's because from what I've been reading, this material is constructed to structural performance standards, not to composition standards. As others have said, it's cheap (unless you buy stainless steel rebar) exactly because it's made from "whatever." One author has experienced different densities within a single rod: weaker spots and stronger spots, which of course means the composition varies within just a few feet.

So the short answer is, nobody really knows, and there is no reference.

Here's the entertaining article I thought actually had the most information - and I read the Wikipedia article; a discussion among blacksmiths; looked in on a study of rebar produced in Nigeria; etc etc blah blah. There are fancier (and more boring) ways of saying what this guy says:

https://makeitfrommetal.com/what-kind-of-metal-is-rebar-and-what-can-i-use-it-for/

I won't speak yea or nay re using it in the garden. Maybe those big long plastic stakes are safer, although the idea of adding still more plastic to the environment puts me off.

I use concrete reinforcing wire, rolled into cages. Really heavy duty stuff, with big 6" holes in it. Had to use a bolt cutter to cut it. It's been very, very slowly rusting for 31 years, I wonder if there's been leaching? To make sure they don't blow over in storms, I've tied them to pounded-in steel T-posts, which are also made of a metal that who knows what its composition is (but at least they're painted). Here are the kind of cages I made in 1989. Still going strong. https://inputgarden.wordpress.com/2011/04/05/tomato-cages-for-the-ages/

Joan

I'd have to guess that there is less lead in rebar (or any steel cord products) than there is in most steel. Lead is added to steel in minute quantities mainly to act as a lubricant for machining. But no one ever does any machining of rebar or chicken wire. That being said, old galvanized steel pipe used to be dipped in zinc, which had an admixture of lead. So while you're removing rebar from your garden, better rip out all your old water pipes.

But it's true. We really all ought to be using organic steel in whatever we do!

I've been using rebar as tomato stakes for over 30 years now (1/2" thick, 10' long). My only concern was that they could act as lightning rods but that hasn't yet occurred as far as I know. They have lasted for over 30 years now so they are very dependable and will still be around long after I'm gone. Rebar was a lot cheaper to buy back then, not so cheap anymore.

I wouldn't worry about steel in the garden as long as we're eating with stainless steel utensils. Myself; I don't lick rebar in the garden.

Rebar is routinely used in barbeque pits, so food is cooked directly on it. Betcha you consume more rebar from that barbeque than from your tomatoes in rebar cages.

I read that rebar might have small amounts of lead in it. Not sure how detrimental or if it actually does just what I read🤷‍♂️ I use them in my garden

If rebar was toxic, a lot of us who have used it for decades would have experienced poisoning my now. ;-) Personally, I would be more concerned about the paint on the T-posts... but not enough to stop using them either.

Urban & suburban gardens have greater issues than steel degradation, since you never know what was done to the land previously. It is far more likely that there is lead in the soil from old paint, or the previous use of leaded gasoline.

Best not to chew on rebar. Plenty of lead in at least urban soils from long-ago gasoline exhaust. Vastly more than would ever come out of rebar. If you import compost, however, and are worried about tiny amounts of lead, might be smart to have it tested.