What is in concrete that would be toxic? Sand, water, gravel, cement. Cement is typically made from sand and clay for their minerals (aluminum, silica, calcium and something else I forget).

The dust from the stuff, I wouldn't think, would pose any problem for the plants in a small amount. I wouldn't want to breathe it in mind you, but don't see how it would harm the plants if it's washed off.

Oh gosh, i hope that's true that it isn't a problem. I think the cement and silica are the bad parts though.

When looking into what pavers to get, i just saw this:

"http://greenlivingideas.com/concrete-and-treatments/can-concrete-be-eco-friendly
In comparison to other industrial processes, cement production is extremely energy- and fossil fuel-intensive, making it the third ranking producer of carbon dioxide emissions (the primary greenhouse gas contributing to global warming).
Aggregate materials like sand and stone that are mixed with cement are mined from quarries, further taxing our natural resources.

Did you know that brick kilns and concrete plants are one of the biggest emitters of air pollution? Making paving stones releases tons of carbon along with harmful pollutants such as SOx, CO, and volatile organic compounds. These toxic particulates can trigger asthma and cause lung cancer. They also end up in the water and food supply."

I guess that is mostly air pollution though, not so much dust in the soil.

Then, there are some studies regarding the silica in conrete and respiratory disorders. Again, maybe this is only breathing it in and not eating it?
http://annhyg.oxfordjournals.org/cgi/content/full/46/3/341

More importantly, there is this info saying that cement dust can cause respiratory illnesses and cancer even:
http://www.elcosh.org/docs/d0200/d000254/d000254.html

In particular, it says:
"6. What about concrete? Can concrete dust also harm you?

* Yes. When concrete is cut, drilled, or broken up, the dust has all the same hazards as the dust from new cement. The only difference is that, since it isnÂt a new product, there will be no label or MSDS to check. So play it safe. "

Granted, I know very little to nothing about these construction materials (I'm a research psychologist by trade).

But, I'm concerned not only for my garden, but these poor workers! We were able to afford them b/c they were cheap. And they worked so hard. I bet they were breathing in all of the dust. I mentioned this to the contractor and he didn't think it was toxic at all, they didn't wear masks or anything.

Not only that, but the factory that made the concrete pavers was local, only a few miles away. On the one hand that was green, since it required no shipping (and fossil fuels) from far away, yet, if it is true about the air pollution, this is our own community that is getting cancer from this! And definitely, this is North Jersey. We're the armpit of America, right - I grew up literally in an EPA defined cancer cluster. Is that a coincidence or is it these materials we don't even think about?

Just wash it off, no need to panic.

Wow, nobody thinks it is a problem to have an inch of this stuff seep into the bed with my turnips, beets and carrots?

Well that's a relief, if not a bit embarrasing...

The hazards of concrete are with the particulate matter, primarily the silica. Airborne concrete dust IS a hazard. But you do not have to worry once you rinse the stuff away.

You probably eat your fair share of silica every day, in the form of diatomaceous earth used to protect stored grains, flours, and the like from insect pests.

Fantastic! Thanks so much for the info. I'm usually a very mellow person, but my garden is my pride and joy!! When I saw everything covered in grey ick I flipped. I am so glad it is ok.

I'm not sure that using recycled pavers would have made any difference. Did you mean second-hand ones that have been used elsewhere, or can you get ones that have been pulverised and re-manufactured? Either way, if your paving guys had to cut them they would have been releasing the same sort of dust. "Recycled" isn't a magic word that makes everything good. In fact if you had used second-hand pavers I would be worried about weedicide residues on them (depending on how old they were I guess).

I hope you wash your veggies. Apart from the concrete dust now in the soil you could have particulates from vehicles on nearby roads and from wood-burning heaters, and bacteria like listeria. So a thorough wash is always a good idea anyway.

One thing you might want to check is if the ph level of your soil has been changed. I have heard that some plants do not like being near newly constructed walls, etc, for this reason. I don't know if any of your veggies might be sensitive to that.

Justaguy forgot the burned lime that is also part of the concrete mixture, that is what cement is, lime. It is not a good idea to breath concrete dust, but in your garden it is not a real big issue, as long as you do not breath it.

macbirch - actually these are the pavers I wanted, made of recycled tires and plastic: http://vastpavers.com/products/composite_paver/general_information.php Which who knows, maybe has its own toxic dust but I didn't think so. Unofrtunately they were $16/sq ft, whereas the concrete pavers were only $9.

Anyway, I always rinse my veggies really well. Just yesterday we ate some of the mustard greens that had been covered in the dust. It was a pain in the neck to get it all off (had to soak, then rinse each leaf, then spin spin spin) but in the end, they tasted delicious - thankfully no grit.

I'm so glad they were still good b/c I brought them along with a ton of herbs, salad greens and arugula to my brother who just arrived home from a double bypass. I figured what better way to be inspired to get well than a boatload of fresh picked veggies! He was really happy.

It was said "might want to check is if the ph level of your soil has been changed"

I seriously doubt that a "dust" layer will significantly change the pH of any soil.

Let the rain wash the stuff off, then relax.

You stated you brother just had a heart operation. Giving him all of the greenry may not be in his best interest depending on if he is taking blood thinners. Too much Vitamin K can change the way blood clots. Hubby loves salads but his blood becomes very thin when he has too much, more than 1 cup a day. Nice of you to give him your treasures but see if his instructions include limiting some types of food including salads. Good luck and long life to your brother.

Best wishes to your brother.

Interesting product. It took me a while to find where it explains what plastic. I always like to know because different plastics have quite different properties. I wonder if it would produce much dust when cut. It sounds like it could be soft to me. Here I've only heard of similar recycled pavers for play areas, and they are soft so they are safe for kids. Interesting idea.

Regarding this post -
It was said "might want to check is if the ph level of your soil has been changed"
I seriously doubt that a "dust" layer will significantly change the pH of any soil.
Let the rain wash the stuff off, then relax.

I don't know because I don't choose to grow plants that are significantly affected by soil ph (think hydrangeas for a spectacular example), but people who do DO seem to take things like nearby building materials and newly built walls seriously. I don't think it's a big deal, you just buy a little tester at the garden centre and if it shows the ph is outside the optimum range I'm sure they'll be able to suggest what to do. Or just wait and see, it might not be a problem at all, but if you notice the next crop not growing as well then you know one possible factor to investigate.
As for the rain washing it off, I imagine the rain will dilute it but in a flat garden bed with presumably friable soil, where is off ?

Thanks for the good wishes maifleur & macbirth. My brother is doing as good as can be now so that's a relief. I did check his food list, and the doctors said lettuce was very good for him so that's mostly what I brought. And "armfuls & boatloads" of mustard greens, well, once it cooks down, you know how that goes - barely enough to taste for the 6 of us that ate dinner with him that night, nevermind a cup each! haha But I will keep it in mind about the vit. K.

I still do need to get my soil tested anyway, I've never had it done yet - I really need to get on that.

Finally, I realized the most ironic thing after this whole episode - all my raised beds are made from concrete blocks! Again, This was the most affordable thing I could find when I built them last year. So if anything was bad in the dust, it would have been crumbling off the blocks anyway! I am so silly. My little backyard is like concrete central. I guess just seeing them covered in grit was the straw that broke the camels back. The good thing is, at least now I know it isn't harmful to the soil.

Your contractor should have had wet saw to cut the pavers. That way no dust, no mess.

It's just great that you can eat yourself to good health in greens! The more greens you eat, the lower the dose of blod-thinner medication.

Have the blood tested monthly to fine-tune medication needs. Don't stop eating a lot of greens. Talk with doc about greens and monthly testing......

All the best for a speedy recovery...

I just had my concrete patio repaired and also have dust all over the plants Hostas esp. Have rinsed them several times and still have white dried dots on everything. What can I use to clean the leaves. they look frosted.

thanks

Water is the only thing. There's no magic product. Just keep at it. Or wait for rain.

I have rinsed off the concrete dust from my shrubs and perennials three times and it is still there. Is there nothing else I can use to remove the stone dust? I'm happy to keep rinsing but how many times does it take?