You might try clear plastic sheeting- it will let light through but no water, and the grass grows well, then overheats and dies. This is pretty fast, within a month in summer. Then you do the cardboard and mulch.
I found free damaged pool covers, and am using those to smother grass and weeds, then putting cardboard and mulch down. Some areas I have landscape fabric, like for greenhouse use, but I’m using the pool cover to start. Gives me a chance to work on one area at a time, not going spring crazy. I have a lot of area that had been a garden, now going to be raised beds and trees.
I will take a picture shortly. My cardboard and woodchips have improved the soil greatly and I have more worms then ever.
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This is about 1800 sq ft of cardboard over sod. I am just finishing an addition and fence around it today. Some of it is about 3 years old and some of it was put in last weekend. The fresh cardboard went in a few minutes ago. I will cover with leaf matter then woodchips or planting beds. The garden is a bit messy right now due to construction.
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None. How many dead earth worm because of gas exchange you have seen?
Earth worms travel to top under the cardboard for several reasons. First, the food source. Second, moisture environment that they prefer. Since earth worms can travel, I don’t think they will choose to stay in a place that can kill them.
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Yes, I believe cardboard is ideal worm habitat.
Gives them access to the soil surface while being safe from some predators.( birds ) They seem to love the cardboard
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I’m trying to do sheet mulch for the first time this year and so far it is working out well. I’m doing it in my Haskap bed and my Gooseberry bed. We will see how long they are able to suppress the weeds this year. my only concern are invasive grasses creeping over the edge, but a string trimmer should keep that at bay. my haskap bed is a foundation planting and one thing I noticed before planting is the cardboard also acts like a wick, pulling water that lands further away from the foundation closer towards the wall where it would otherwise remain dry under the eaves.
I think that corrugated should work beautifully for the job, although if you have the time and resources, collecting free cardboard should work just as well too. I would go with one layer of A flute, but that’s just me. newspaper in 5 sheet thickness or a single layer of 60# Kraft paper should work as well, although I expect corrugated cardboard to be much stronger at repelling weeds and the airspace may help retain moisture underneath (just an educated guess).
good luck and keep us posted on your test. would love to see some pictures!
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I sheet mulch with cardboard a lot. It works great except for invasive grasses. Not sure why but they seem to love growing roots through the layers of cardboard. Much much better than pulling all of the organic matter off the soil and applying mulch IMHO.
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Those cardboard prices seem to be about what you’d pay for black ground cover, which you can reuse for years.
What do you mean by black ground cover?
Something like a silage tarp could last several years depending on how many mils thick it is but silage tarps repel water and are not made to be left on and grown through. they can be useful in commercial applications but how many people are going to be using a silage tarp more than once to cover a 1,000 sq foot area? Also once you pull it up you are left with exposed dirt that is primed for weeds.
If you mean landscape fabric these can be moisture permeable but they need to be covered by stone or mulch anyway and since they don’t decompose they don’t add anything to the soil like sheet mulching will. I always just found landscape fabric to be a pain as I’m weeding as roots will grow through it and make it harder to remove them because the landscape fabric anchors them to the bed. just my 2 cents.
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I have used X-Board from the hardware store and it works great to kill grass, it will last about a season in my climate before it is broken down.
https://www.homedepot.com/p/TRIMACO-35-in-x-100-ft-X-Board-Surface-Protector-12374-6HD/304700514?MERCH=REC--searchViewed--NA--304700514--N
Do you take the box tape off? I tried this once with used boxes and ended up with strips of tape everywhere under the mulch, which was not a huge deal but a bit of a mess.
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It is woven black poly, there are holes punched so water can get through, but it does tend to pool or runoff quite a bit until it has been worn in a little. It can kill the grass in a few weeks and then get moved before the chips go down. Though if perennial weeds are involved it would need to stay down much longer, and cardboard might be a better option.
It can be used the same way as silage tarps for stale seedbeds, or no till, but can be secured with sod staples and will last 5+ years.
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Get a big roll of kraft paper off amazon or staples
I don’t take all the tape off. I layer a few inches of mulch or woodchips each year and the garden is no-till. Haven’t seen any tape surface yet.
Do you have a source of information which confirms this statement? I have read countless articles and books with the opposite viewpoint, and have personally seen the benefits of adding a cardboard layer in my own planting beads. I had at least 4 earthworms in each of the tiny holes I dug for my gooseberries this year after installing my beds last year. The robins love hunting all over the beds, I watch them do so daily from the abundance of worms.
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I have never tried just putting down cardboard on top of my field grass then compost and mulch…
Seems to me you would have a layer of good stuff then immediately under that a layer of compacted soil in whatever shape it was prior.
I may be somewhat old fashioned with tilling… but it works great. I normally till up a 8 ft wide strip of field. Just 4-5 inches deep… this breaks up all of the grass and grass roots… and mixes it with the soil… composting it… I usually do that a couple times over a couple weeks… then I will add compost and till that in or layer it in… and I will then rake that 8 ft wide strip up into a 4 ft wide raised bed… then just cover it all with a deep layer of mulch.
I like to do this the summer before… then plant it in the spring.
When I rake that mulch back to plant in the spring the soil is in great shape… deep and lose and loaded with earth worms. I can normally plant even fruit trees using nothing but my hands.
You don’t have to use cardboard if you do that… grass does not come up thru my mulch.
I can see how that should work well if you were absolutely against tilling.
I have a hard time believing that a layer of cardboard or anything cardboard sized would actually kill earthworms. Any time you find just about anything large/flat laying on the ground (lumber, plywood, sheet metal, carpet, etc.) and turn it over… you can usually collect enough for a fishing trip.
TNHunter
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Sheet mulching with paper or cardboard works. I erase parts of lawn with just a thick mulching of hay/straw. Sheet of plywood? black plastic? Yep. Its all about blocking the light. Just mow it really short first. It will be gone in a month.
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Linda Chalker-Scott and her students have a few papers on gas and water exchange across different sheet mulch materials (link). The short of it seems to be that wood mulch alone ( particularly a large format arborist-type mulch) is sufficient to kill many lawn grasses by elimination of light, while still allowing gas and water exchange. Cardboard limits exchange and can become hydropobic if allowed to dry (e.g. exposed edges if mulch is dislodged). However, it breaks down relatively quickly and can subsequently be recolonized by soil life. Newspaper is much worse for gas exchange and takes longer to breakdown. My two cents is that cardboard is probably fine, but straight mulch is better if you can apply a sufficiently thick layer. However, card is probably fine the long run and if you go with cardboard, the less coated the better.
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I let the worms do this for me! 
having the grass>cardboard >compost >mulch, I am at a minimum of 4-6" of soft, happy soil high in organic material mimicking the forest floor. I am sure this method does not work as well in all climates, but on the east coast it’s a great low labor way to go. Those worms do a good job of breaking up the hard “crust” as they munch on the grass above it.
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literally my whole property was planted like this. after losing 2 apples by trying to grow in ground i went to 12in high raised beds and mounds. put down a larger area than needed of double cardboard, mound soil on top or fill a raised bed . planted tree/ bush in them and mulched heavily w wood chips. i planted every thing in rows so i eventually filled in between the trees with cardboard and woodchips so i didnt need to mow around the trees. just go up a row and down the row. i then in the last 3 yrs., been planting mecinidals and fruiting groundcovers in between and around the trees and bushes. its filling in nicely with all types of plants and bee attracting flowers. once its grown in enough it should fill in so it will have a tunnel effect when walking the rows and shade should keep the grass from growing much or at all. 
you dig in those chips ive been adding in there for 7 years now, and its about 8in. thick of nice black soil with tons of worms. the mounds and raised beds settled some but are still growing great plants/trees. if i planted these directly in ground they most likely would have died in my rocky clay soil. cardboard and woodchips kept me growing when it looked hopeless other wise. and of course great ideas from you great folks here and on permies.com.
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