Do you have any reason to suppose that the soil in your own plot is likely to be contaminated with heavy metals? Is it former industrial ground? Is it very urban? Alongside a heavily used road?

I’d start with a soil test. If there is no specific evidence for contamination you can simply use the native soil beefed up with compost. There is no need to introduce an entirely new, expensive, load of growing medium.

Plant uptake of heavy metals is a complicated subject but generally, not an issue of huge importance to most gardeners. The soil must be heavily contaminated and the metals themselves in a fairly soluble form to be taken up in any kind of significant concentration. That is seldom ever an issue in most cases :-))

The "ideal" raised bed soil media is the same as what is in your garden - a mineral based garden loam/topsoil and some added organic matter, like compost. Peat is unnecessary and overly acidic. And vermiculite adds nothing of value. Pretty much a waste of money to include :-)

In my state, ALL fertilizers and packaged soils are tested for heavy metals. I would not hesitate to use any packaged soil mix intended for raised beds or for amending planting areas.....but NOT a potting soil! But since packaged or bagged soils are far more expensive than buying in bulk, I suggest clients access bulk soil mixes.....either a garden planting mix or a 3 or 5-way mix (pretty much the same stuff - just different names). These tend to be screened topsoil blended with compost and some sort of drainage enhancement.

In Oklahoma peat is likely to break down and vanish completely after only a year.

This is such great info! Thank you, everyone!

I live on a fairly small lot in a development, so I'll need to bring in soil as I don't have any available to transplant to the bed.

That is great to know about peat and vermiculite, too! Sounds like I just need to locate a bulk soil mix locally. There is a company very close to me that sells bulk mixes and advertises their use for gardens. They seem to be a very reputable company, so I bet I can ask them about the quality/metals testing.

I'm looking forward to coming back for more advice! You guys are awesome :)

< Peat is unnecessary and overly acidic. And vermiculite adds nothing of value.> I agree and neither offers any plant nutrients.

Always begin with a soil test but be sure the place you plan to plant and what you will grow will get enuff "direct unshaded sunlight". This can change when any trees have foliage on them so start small but leave room to grow.

Not sure where you are located but be sure to get a professional soil test not just a pH test from the local garden center. You can (and should) have any compost you buy tested first.

I like to mulch about 4ft around any garden beds to keep the weeds down.

Also keep in mind the garden center is there to sell you things whether you need them or not - not to solve your problems. Contact you local Ag Dept. or Master Gardeners for help with problems.

Good Luck

afaik - to test for heavy metals or anything toxic you would have to specify what elements you want to test for and only certain labs will do that. Normally, a professional soil test is a good starting point.

Environmental chemist working in contaminated site remediation here. What everyone said is true: no need to worry about contaminants unless you have some specific info about the source. Soil everywhere has background levels of metals, so if you did a specific test, you would find natural levels of lead, arsenic etc. Rare to find it elevated to such an extent that it's toxic. Even in cases where soil is contaminated by lead from house paint, leaded gas emissions, etc., the main exposure risk is not plant uptake but ingestion of traces of soil clinging to root crops. If you have an old urban house, you can get a test for lead pretty cheap and go from there.

If you are importing soil it's a good idea to ask the supplier where it came from. Usually it's going to be a rural farm or new development site, creek bottom, etc. And LOOK at the product. If you don't like the looks, if you see debris or trash in it, keep shopping.

But I have to ask, how is the native soil in your yard? Are you really sure you need to import soil or can you just amend what you have and grow directly in it? Unless it's really horrible - like very heavy clay with low organic matter - you can probably work with it for less $ and work.

Bottom line, of all the things you have to worry about as a first time gardener, contaminants should not be at the top of the list.

PS I would like to see what you are reading about metals in store bought vegetables though, just out of curiosity.

Unless your plot is concreted over or has had the top soil scalped off there should be some soil there to start you off, however small your lot. Although you want to have raised beds you can garden in ground in the native soil perfectly well. Many people do. Just keep mulching with compost. Who knows you may find you don’t actually like gardening, so starting with the cheapest option seems sensible to me.

Unfortunately, I can't do ANY digging, due to not knowing where our (very shallow) sprinkler lines are. My husband has strictly forbidden it LOL So bringing in soil is my only option.

I did check with the one of the local soil and rock materials business, and they don't do any heavy metals testing. I keep thinking I shouldn't worry about it, but then I read that some compost/soil blends have sewage runoff included in them, which would contribute to the likelihood of heavy metals being present.

I initially became aware of this when The Clean Label Project released their research results on baby food in 2017 (White Paper link below).

I've grown up in agriculture (livestock mostly, but crop farming on my husband's side of the family) so I completely understand how some information found on the web is not fully reliable, or is there for the purpose of scaring people into purchasing from a different market segment. Ultimately, I want to start gardening so my son (1yr now) will be able to experience agriculture in a hands-on form, since we live in the city. My grandparents always had a HUGE garden that I grew up helping cultivate, and I want to share that joy with my child :) Preferably, without ingesting any harmful chemicals lol

Clean Label Project White Paper:

http://www.cleanlabelproject.org/app/uploads/clp-white-paper_baby.pdf

I can't attach the PDF of this article since I'm accessing it from a university library, but here is the citation:

Khan, A., Khan, S., Khan, M. A., Qamar, Z., & Waqas, M. (2015). The uptake and bioaccumulation of heavy metals by food plants, their effects on plants nutrients, and associated health risk: A review. Environmental Science and Pollution Research International, 22(18), 13772-13799. http://dx.doi.org.prx-herzing.lirn.net/10.1007/s11356-015-4881-0

Consumer Report - Arsenic:

https://www.consumerreports.org/cro/magazine/2012/11/arsenic-in-your-food/index.htm 

Yes, some bagged 'soils' include 'Municipal Waste' products, but as far as I know, they are always listed as such on the bag. It's not difficult to avoid such items. However, you'll need so much, even for a small bed, that purchasing a bulk 'garden blend' from a local nursery or compost supplier-type place will be MUCH cheaper than the many bags you'll need. In fact, once you get a quote for the amount of soil you'll need, if there's a concern, your husband might suddenly find the incentive to get out there and find those sprinkler lines.

What exactly do you mean by "sewage run-off"? Human waste sewage?? In most areas of the US, that is extremely highly regulated and fertilizers or soil products made from processed sewage (aka 'biosolids') are equally heavily regulated and controlled. In fact, there is likely less risk of heavy metals occurring in these products than a similar product with another source material!

Did you ask the bulk soil supplier the source of the material they sell? Unless there are Superfund sites nearby, I doubt you have much to worry about :-) And while it may be a more expensive option than purchasing in bulk, you can always purchased commercially prepared bagged soil/raised bed mix. And start making your own compost.

I really think you are over thinking this and being unnecessarily cautious.

If you are adding compost and/or mulch, you don't necessarily need to dig, you should be able to plant directly in or just under the layer of compost, let the plants' roots do the work of tunnelling any further. There are lots of sources to give advice on how to plant without doing much digging, depending on what you are planting. You may want to look up lasagne gardening/composting. Obviously there are some common sense guidelines and things to be aware of, you usually won't want to plant directly in a deep deep layer of wood chips, for example. If the compost is 'done' (I'm going to avoid defining that for brevity), should be fine. Since you'll probably want to add compost (organic matter) anyway, just skip the digging part. (Granted you might want to dig for other reasons, but it's not strictly required).

A good soil to use in raised beds is loam. Loam is not easily found but some soil suppliers do mix something close, about 45 percent sand, 25 percent clay, 25 percent silt, and 5 percent organic matter. As Tox stated above take a good look at whatever soil is being sold, and smell it. Good soil will have a pleasant aroma and that pleasant aroma comes from the bacterial activity in a living soil, no odor/aroma dead soil. Unpleasant odor/aroma or a putrid odor indicates a soil that will be a problem.

Topsoil is simply a soil from the top of the ground and has no magical properties, it is whatever was scraped off someplace and may or may not be what you want.

A few thoughts on contaminants. The number one biggest thought being as follows: The dose makes the poison. This is a quote from Greek philosopher (which is what they also called scientists back then) Paracelsus.

What it means is that there is a dose-response relationship for most toxins. The more you are exposed to, the higher your risk.

The problem with trying to achieve 'no toxins' in your food is that there are minute levels everywhere, as you can see from CR's analysis of 88 juice products for arsenic. The video said that 10% of the samples exceeded federal safe drinking water standards. Now I'm not saying that's a good thing. It's very likely those same brands sampled a month later would give different results, BTW. But keep in mind that drinking water standards are based (mostly) on consumption of a certain volume of water per day for a long period of time (0-6 years for children, lifetime for people over 6 yrs). Are drinking water standards appropriate to apply to juice? If your kid is drinking more juice than water, that's probably not a good thing to begin with, but they are probably drinking less. How does that translate to overall As exposure? What about all the other foods?

And more to the point for your original question, how does the level of metals in your garden compost or soil affect exposure for your kids? This is a very complicated question because it involves transfer of contaminants from soil (or soil organic matter, but for our purposes we'll just call it all soil), to vegetables (either by uptake INTO the plant or soil sticking to the outside that is not washed or peeled off). Then absorption from the GI tract into the body (which is not 100% efficient).

There are established 'safe' levels of contaminants in soil for residential yards, and the numbers include gardening in the soil. When you add compost to soil, it is diluted by a huge amount. We usually assume it is mixed into the top 6" of the soil. So the addition of X grams of contaminant to Y square feet of soil will result in Z ppm increase in the total level in the soil. Metals do stick around and don't decompose, so once they are there they pretty much stay there. But you might be surprised how much lead or arsenic can be added to a garden plot before the levels exceed those considered safe. BTW most soils have background levels of all these metals already. Usually well below safety limits (unless polluted by urban air deposition, lead paint flaking off the house, etc.).

The point is, even if you had sampling results from a bag of compost, it doesn't tell you a lot. And you won't normally get that. Some cities (mine included) periodically test their municipal compost and post results. About the best you could do is compare it to another brand you had results for and select the lower one.

As for biosolids (sewage sludge), there is a federal rule limiting the levels of scores of chemicals in sludge that is to be reused or applied to crops. I personally would probably avoid using sewage biosolids on my vegetables but probably would use it on my lawn if it was the best or only option available. I haven't seen any around here. The biosolids rule is somewhat controversial, especially with respect to metals, since they accumulate over time.

We haven't even gotten into the fact that many toxins are less bioavailable when organic matter is high, or the fact that your home and car contain many toxins as well. I'm not trying to minimize, or overdo either.

With so many variables, I certainly can't blame anyone for just flat out trying to minimize exposure where possible. It's really the only approach. I suggest that growing your own food with minimal or zero pesticides is one of the best things you can do. And that any compost is better than none for making them generally more nutritious.

Great comments, thank you!

I definitely am not a toxiphobe...I drink from water hoses, was pretty much raised in a barn, and was exposed to all kinds of chemicals over the years working as a professional horse trainer and on breeding operations. I am hopeful to reduce exposure, as many of you have mentioned, when at all possible.

During my pregnancy and since nursing my son, for instance, I stopped using a few products that can be transferred and potentially harmful to the fetus and nursing infant. I realized it was really easy for me to find alternative products that were equally as effective, and actually less costly (example: I swapped three expensive acne products for a homemade mixture of grapeseed oil and tea tree oil). My skin looks better than it ever did with the other products, as an added bonus!

I'd like to apply these same principles to my gardening venture. I want to be educated and aware of creating a good soil "product" that will last and help yield delicious and nutritious food for my family.

I really appreciate so many of you putting my mind at ease. I feel much more comfortable purchasing a bulk mix, knowing the questions to ask the producer and such. I also feel more comfortable using my native soil, whenever the opportunity for that arises, too.

Many thanks, everyone! Time to start building my bed's frame now :)

More important than bed frames is the issue of tree roots and shade. They are killers to good gardens. Frames may be nice, but not necessary.

Loose, friable soil is so nice to work in. Compost and other organic matter is so good for fertile soil...some fertilizer may be helpful too, especially to get mineral levels up.

For heavy clayey soils, some sand can be permanently helpful....even some peat moss.

Gonna disagree on the adding sand to lighten a clay soil :-) To do so successfully .....and not just create a concrete-like substance......you need to add at least 50% of the soil volume as sand. And peat is a poor substitute for actual organic matter, like compost. Which is still your best bet for loosening or lightening a heavy clay soil.

I will resist the urge to nitpick that peat is actually organic matter. Of course I agree that compost is better, as it will continue to decompose whereas peat is pretty much 'done', not to mention that compost can be obtained locally. Oops I think I *did* mention it...and I nitpicked too...<British accent> "Sorry!"

LOL!! Of course it is "organic" matter as it is derived from plant material. But it is already decomposed organic matter so not attractive to any soil organisms, has no nutrient value and is of too small a particle size to be of value in lightening a heavy soil. And is unnecessarily acidifying, unless you need that attribute.

'I will resist the urge to nitpick about compost' followed by the inevitable = Gardener's apophasis

I'm not going to admit that I remembered the rhetorical device, but had to look up the proper name for it.

ha

Dr. House: "I don't want to say anything bad about another doctor, especially one who's a useless drunk."

gardengal 48,

Most soil already contains some sand...likely 25% or more. I added 2½ to 3 inches of mixed sand, so I did not make concrete. Local 90% sphagnum peat moss does not break down quickly for nutrients...THAT IS THE BEAUTY OF IT!!!

By the way, I loooooove the results. You do not have to love the results...your loss.

I do also love adding organic matter and love my fertile and loose dark soil. I also like many of the posts you make and toxcrusadr.

Most every knowledgeable person on soil, i.e. soil scientists, will tell you that to make much difference when adding sand to clay you need to add 45 to 7percent sand to the mix.

Perhaps this article might be of interest.

http://www.patwelsh.com/soils/never-add-clay-to-sand-or-sand-to-clay/

Well it all depends on what you're starting with, and wayne has illustrated nicely that there is absolutely no substitute for direct experience with one's own soil. If it works, it works. My purpose whenever I warn someone about the sand and clay issue is just to give them a heads up if they didn't know about it. One has to make one's own informed decisions based on local conditions.

Thank you toxcrusadr for the excellent post.

You explain things well there in a few words...getting right to the point.

I have read many old farm books on Cornell Agriculture Library saying that sand can amend clayish soil. Yes, it can make a looser soil to soil that is a bit tight and 'heavy'. I have good soil and when I retired, I took seriously the project of amending my gardens...about 8,000 sq. ft. This makes a test over 3 soil types. A person can often see the soil types on the internet for THEIR property.

I have added a LOT of organic matter and also minerals....leaf compost, leaves finely chopped, horse manure with a lot of hay [yeah, I get some clover sprouts] , I chop up well the residuals in situ

Did I say I love the local peat? !!!

I suspect I have silty clay rather than pure clay, so the occasional sand that I did add over the years made more of a loam than a sandy clay concrete. And as you say organic matter mitigates texture issues too. Compost covers a multitude of evils.

I have mostly silt loam, The heaviest corners are silty clay loam.

As I said above somewhere, In 50 foot in one garden and 75 foot in the 2nd garden [the 3rd is flat ], I have 3 soil types. They have a very nice slope of about 1%. At the top end the original soil before amending was a lighter color and worked up lumpy...with fall plowing. The middle was loamier and darker brown. The lowest corner was nearly black and worked up like sugar if fall plowed...but a bear if spring plowed.

I don't moldboard plow anymore. The very upper end was a bit of Glywood soil. The middle is Blount. The heavier corners Pewamo.

About 4 miles from me there is a change in the soil types...mostly Brookston nd Crosby. Brookston and Pewamo are very rich soils, but tend to be low lying and damper in spring.

Here is a site that can be moved around after you figure that out.

https://www.acrevalue.com/soil/IN/Madison/

It sure can change a lot over a small area, even in natural conditions. And if soil is moved around for construction, all the rules go out the window.

I've looked at soil maps for my area and even from the top of a 25 ft. rise to the valley below, there can be 2-3 distinct types of soil due to historical erosion, drainage and native vegetation.

This is a Soil, along with compost and mulch site. It seems so many talk about having 'clay' soil. I suppose that getting into just what type of soil one is dealing with comes down the line a ways. I find it interesting.

Below is a link to a 'soil series '. You can type in "soil type" on Google Search and you are good to go from there

.Sable Soil Series