To Cardboard or Not to Cardboard?

To cardboard, or not to cardboard? My 1/2 acre urban yard in a Superfund remediation zone has been excavated to 1', and backfilled with roughly 1" of clay, 4" of sand, 4" of topsoil, and 1" of composted cow manure. They are getting ready to install 2" of pine bark nugget mulch. I will be planting a permaculture food forest with over 70 fruit and nut trees, guild plants, vegetable and herb beds, etc.

The whole thing is pretty pristine at this point but a few weeds (or grass?) have sprung up. Should I put in a layer of cardboard before the pine bark nugget mulch as a preventive weed barrier? Or is it silly to put in the time and effort if there's not a lawn or ton of weeds to kill?

One school of thought says it will block weeds, add carbon to the soil as it breaks down, keep the soil cool and moist, and attract worms.

Others say it can block oxygen and water to the soil, attract snails and slugs, doesn't add much nutrition to the soil, and will only block weeds for a year or two. I'm also worried that the pine bark nugget mulch and cardboard are both dry browns that will only decompose really slowly, although I will have underground drip irrigation. Could this smother and kill the bacteria and organisms beneath? Or am I making that up?

Can anyone offer educated expertise on this matter? There's a lot of guessing, figuring and surmising on the internet. Thank you!

(Only first picture is my yard, with compost done in the back, topsoil so far in the front. Others are from other homes in the remediation zone.)

So there are people on here whom I'm sure will disagree with me re:cardboard. But in my opinion - use it. And wet it WAY down before putting chips on over it.

Some will say that cardboard is Gicky - but as you are already dealing with a superfund sight that should be the least of your worries before eating anything you grow. Also in my personal experience, every time I leave a piece of cardboard somewhere long enough to exclude plants when I pull it up there are lots of worms wriggling around under it in all of their casings. Worms have skin just like us. Actually I imagine its an even more permeable membrane.... Anyway - it cant be too bad if they are wriggling around.

Worms hate sun. Cardboard blocks sun. Use cardboard.

*Ducks, covers, and waits for the verbal bombs to start flying*

Edit: Spelling
Edit 2: Grammar
Edit 3: Spelling of "Grammar" :/

Kayla Wildflower wrote:

(Only first picture is my yard, with compost done in the back, topsoil so far in the front. Others are from other homes in the remediation zone.)

For whatever reason I'm not seeing the pics. Others?

cardboard will stop weeds coming thru, mulch on top

same amount of mulch no cardboard: weeds come thru same season, they can be pulled quite easily, but the total esclusion of light from card kills it off, however, year 2 they will come thru, so only use year 1 if you have a lot of weeds to smother asap imo

Frankly with less than 12 inches of soil (sand+clay+compost) over a superfund site. I would not eat vaggies or herbs or roots or nuts or mushroom from it. I might be tempted to eat some fruits, only because they dont have minerals/metals (inclusive of calcium and chromium/lead/arsenic). Pretty much all of your plants will send down roots below that 12 inches and start feeding you super polluted food. We are not talking about a little bit of lead from lead paint from oil house. Which so many people are afraid of we are talking about a superfun site. I would only eat food that you grow in a container.


now back to your original question. Add cardboard and then add another 18 inches of compost on top of the mulch out of your own pocket. Maybe it will cost your an extra $3000+ put it will so worth it.

S Bengi wrote:Frankly with less than 12 inches of soil (sand+clay+compost) over a superfund site. I would not eat vaggies or herbs or roots or nuts or mushroom from it. Pretty much all of your plants will send down roots below that 12 inches and start feeding you super polluted food.

now back to your original question. Add cardboard and then add another 18 inches of compost on top of the mulch out of your own pocket. Maybe it will cost your an extra $3000+ put it will so worth it.

Actually, 30 years of testing have shown the contamination is from airborne dust from the factory down the street, and thus is exclusive to the top 6" of soil. They are removing the top foot just to be safe, and replacing it with EPA top grade soil, so I feel better than the average person eating food that I'll grow there.

As far as 18" of compost costing $3,000, I just purchased .82" of compost - yes, less than an inch - and it cost $2,050. That's 82 yards at $25/yard. (7 truckloads of 12 yards each, took two days for delivery.)

Whoever says dirt is cheap hasn't bought any!!

And that is dead dirt, soil and compost are gold.

Landon Sunrich wrote:

Kayla Wildflower wrote:

(Only first picture is my yard, with compost done in the back, topsoil so far in the front. Others are from other homes in the remediation zone.)

For whatever reason I'm not seeing the pics. Others?

Yeah, I'm not seeing the pics either. I don't know why you can't just upload photos to a post - it has to be a URL link. Last time I just uploaded pics to my Google + profile and used the links from there. Tried that again this time and it didn't work.

Another option is using a link from a Facebook pic, but I didn't know if that would work on a public message board. Anyone have other tips for how to include photos on permies.com boards?

Tim Wells wrote:cardboard will stop weeds coming thru, mulch on top
... only use year 1 if you have a lot of weeds to smother asap imo

I'm starting to come to the same conclusion - it's probably not worth doing as a preventive.

Well as long as you did multiple heavy metal test of the soil after the scrape and it came back as healthy, then you are good. With only 0.82 inch of "real" soil. I would skip the cardboard and just add more mulch up to 6 inches of it.

Kayla Wildflower wrote:

Another option is using a link from a Facebook pic, but I didn't know if that would work on a public message board. Anyone have other tips for how to include photos on permies.com boards?

You can upload images as attachments - here are the instructions How to: Include Photos or Other Attachments in a Permies Posts

They will work from facebook if the album is permies. I'm not sure about google plus but I suspect their permissions are a bit strict.

Kayla is probably safer eating food off her cleaned up site than anybody growing food grown in an urban area. Urban areas are polluted and nobody seems to notice or think about it. And look at all the little urban gardens popping up now in cities across the USA. Uh, but come to think about it, those people breathe that urban air in every day and live with the contamination getting on their skin every day too. Not my cup of tea. I was raised in a big city (where the snow turned blackish, the surface of puddles after a rain had 'rainbows' on them, and cars used leaded gasoline) and am glad to have left it behind. I enjoy an occasional visit, but the constant exposure to the pollution is something I'm no longer willing to live with.

Su Ba wrote:Kayla is probably safer eating food off her cleaned up site than anybody growing food grown in an urban area. Urban areas are polluted and nobody seems to notice or think about it. And look at all the little urban gardens popping up now in cities across the USA. Uh, but come to think about it, those people breathe that urban air in every day and live with the contamination getting on their skin every day too. Not my cup of tea. I was raised in a big city (where the snow turned blackish, the surface of puddles after a rain had 'rainbows' on them, and cars used leaded gasoline) and am glad to have left it behind. I enjoy an occasional visit, but the constant exposure to the pollution is something I'm no longer willing to live with.

Very true it sounds like her soil is safer than mine. I only eat fruits from my garden, currently afraid to eat veggies and herbs from it.

Su Ba wrote:Kayla is probably safer eating food off her cleaned up site than anybody growing food grown in an urban area. Urban areas are polluted and nobody seems to notice or think about it. And look at all the little urban gardens popping up now in cities across the USA. Uh, but come to think about it, those people breathe that urban air in every day and live with the contamination getting on their skin every day too. Not my cup of tea. I was raised in a big city (where the snow turned blackish, the surface of puddles after a rain had 'rainbows' on them, and cars used leaded gasoline) and am glad to have left it behind. I enjoy an occasional visit, but the constant exposure to the pollution is something I'm no longer willing to live with.

Ugh. If you look at the types of houses and neighborhoods with lead contamination in the soil around the house (from the paint washing/chipping off over the years) and the types of houses and neighborhoods that host SPIN farms--there is a correlation.

R Scott wrote: Ugh. If you look at the types of houses and neighborhoods with lead contamination in the soil around the house (from the paint washing/chipping off over the years) and the types of houses and neighborhoods that host SPIN farms--there is a correlation.

Have studies been done indicating produce grown in urban areas or "the types of houses and neighborhoods with lead contamination in the soil around the house (from the paint washing/chipping off over the years)" is less safe than produce grown elsewhere? I tend to doubt it. Some of these comments sound rather judgmental.