Bark, which many people erroneously call wood chips, dont absorb water and create dry soil conditions below. But there is solid evidence that no mulch will change the pH of soil. Here is a fact sheet that talks about arborist chips and those concerns. Compost does not make a good mulch. As the abstract also states, a more complex landscape with more life will have different results. Then I can walk around freely and let others do the same. Thats the state of the science, and its up to proponents of cardboard mulches and/or lasagna mulching to provide evidence that our study was incorrect. Without some sort of comparative experimental study you can only guess what your cardboard is doing. Im not asking about an extreme condition where diffusion is zero. You need to make sure there is not a population on adjacent land that is sending roots into your property. unfortunately to access the link, one has to be a member, Im curious to read how this last commenter will sort out his clay dilemma. I thought about putting down a layer of cardboard, cutting out a 4-inch diameter circle in the center of each square-foot, and planting inside that area. Diffusion rate needs far more correlation to soil life before I can make that connection. We dont have time to clean up science. Made from used pallets or used lumber, this mulch breaks down slowlyand is recommended forpathways. That is certainly not a desirable outcome for any garden or landscape. What about immediate results, like in the first week? Using 20% acetic acid try to kill the really nasty weeds. Third, lay down another layer of arborist chips. Then, the field work can be better analyzed. Please note that the tree trimmers will drop a full load up to 20 cubic yards and the availability of this mulch is seasonal. Fritz, if I was going to use cardboard I would grab it from workI work in a bakery and there are big pieces of plain cardboard that are used with pallets. At the end of the season I plan to take the cardboard up and let nature do its thing in the FallI let the leaves fall and dont clean up until spring. 3) Once weeds are under control, then the level can be maintained at 4-6. Results may differ in drier climates. Compost is plant and other organic matter that has gone through a decomposition process. I will not use heavy duty pesticides as we dont want to contaminate the ground water & well. Otherwise, light can filter in. So no, I dont recommend using newspaper. This is called anecdotal evidence and does not lend itself to any kind of objective analysis as there is no control, no replication of treatments, and no data collection. Yes, @Nolan Archer, we are stopping weeds, and as surprising as it may seem, it works a treat. Interesting debate about science here, which Im not going to jump into. Seems pretty obvious conclusion. Hi Linda! Do not ever plant into the chips. And to figure out what to do about the area I have already sheet mulched, some of which I have already planted into. Copyright 2022 Lyngso Garden Materials, Inc. All Rights Reserved. Is there a way I should try to kill the weed seeds before mulching? Id wager that if people tried a cardboard bed versus a mulched bed theyd see that the cardboard isnt the miracle they are perceiving. Fresh chips are not a problem, anyway. I would wait until the mulch has done its work, pull the chips back, then build your mounds or raised beds. You get NO weeds with wood chips if you use a deep enough layer, and they dont interfere with water and gas movement like sheet mulches do. If they are discussions about specific plants (i.e., temperate vs. tropical), then there could be regional differences. Is there a published research paper somewhere that Ive missed? Yet you have no direct evidence yourself at the moment for why lasagna mulching doesnt. Ill guarantee thats what you were seeing under the plastic. I know that wood chips are preferred because theyre 3 dimensional. In the meantime, you might find this manual useful: https://pubs.extension.wsu.edu/scientific-literacy-for-the-citizen-scientist. Weve all observed that earthworms crawl to the soil surface during heavy rains; this is due in part to water filling their burrows and reducing oxygen availability (Chuang and Chen demonstrated this nicely in 2008). I think earlier you mentioned that theres no funding for a more in-depth cardboard mulch study and I think thats a real shame. On the other hand, there is ample evidence, both theoretical and practical, that sheet mulches inhibit water and gas movement while coarse, chunky, three-dimensional mulches do not significnatly interfere with either gas or water water exchange. Thats what we have done, and thats how commercial composting companies keep their materials free of roots. You may dismiss the experience on which we rely as anecdotal and therefore irrelevant but if you do you may end up dismissively applying the word anecdotal to such a vast range of useful knowledge and experience as to make the word useless. This doesnt meet the standard of reliable evidence. This entire process is very attractive to nematodes (earthworms and other soil animals), bacteria and fungi, which as they crawl toward and through the cardboard actually open up pockets where gasses and moisture can transfer, both from the atmosphere and from subsoil. I would like to actually improve the soil. This isnt rocket science. As responsible gardeners, we must consider where all this woodchip is going to come from and what this ultimately costs. I am trying to kill the goutweed currently growing in the parkway (between the street and sidewalk) in front of my house. Did I do permanent damage with my tarp? It should not smell putrid or strongly of ammonia. I am having a problem with weeds in several long and narrow sections at my home. Sandy and silty soils are nutrient poor. Was thinking of planting mint. Interior soil conditions are always more moderate than those at the surface: cooler in hot weather, moister in dry weather, and so on. I am no till lasagna. As someone who gardens mostly with native plants, I am not interested in attracting earth worms due to the competition. Hi, I appreciate your blog and professional approach to research and conclusions of the issues discussed. Hopefully that is good enough for you. What you need to provide is evidence that lasagna mulching *does* improve soil health and worm density. Grab a handful and smell the compost. We need to eradicate this destructive instinct to digging. I came to this page seeking more confidence in applying cardboard sheet mulching and have come away almost as unclear as I arrived (which may be a good thing). Wood chip mulches are the best mulches, without compare, for soil and plant health. You will need to sow densely because there will be weed seeds around as well. Then leave everything for two months without touching it. Would it be possible to use those paper yard waste bags or is that basically the same thing? I assume you want to keep your soil healthy so I wouldnt smother it with cardboard. Its recommended to use a minimum of 10 replicates and 20 is ideal. i have been using mostly grass clippings and pine needles and little leaves and wood chips. I just want to say thank you so much for considering all the soil life (worms and other invertebrates, microbes, fungi, etc) and doing so with science. I wonder why worms congregate under plastic that has been left on concrete? To be honest, I never wear a mask. I look forward to your reply. I will drill 30 inch deep holes 3 feet and beyond from the 12 ft tall trees, nut trees. Sonia. insects) will cost you money because it is slow, painstaking work. to lay woodchip to the level you suggest (4-12) in our gardens. Arbor mulch works great for lawn conversions andcan be made from many kinds of trees. About 2500 sq ft. is vegetable garden and orchard. And at the end of the day, nothing exists except atoms and empty space. Science evolves. It is a beautiful sight as the wildflowers surrounding them explode with health and vigor. Im hoping you offer some suggestions for how to establish a small prairie yard for our western Washington location. Sixteen days without oxygen will kill you. Did you think of testing the effect of a layer of dead deciduous leaves on gas diffusion, which reflects the conditions of a deciduous woodland floor in autumn / fall? In the article you helpfully provide a link to your 2019 paper. Your own reasoning begs the question so what? In fact the corrugation in cardboard is ideal for leaving pockets of permeability. alte Kartons & Pappe im Gemse Beet? If you know otherwise, please let me know. Bermudagrass is the predominant turf grass where I live, and it is great as long as it is where you want it. When stuck together, as a damp mass, they could have fewer air pockets and are certainly less three dimensional than woodchip. I have been using same pieces of lanscape cloth in vegetable garden for several years. Also, as a side note: Dismissing gardener and folk wisdom (often gained through generations of painstaking trial and error and high attention to local microclimate detail) as simply anecdotal information and overly relying on dubiously funded science as fact is very dangerous, especially right now given corporate interest in trying to shut down grass roots food sovereignty movements. Everything added during cardboard manufacture is designed to create a product that resists wetting and decomposition. Those are constants for each treatment that will not change regardless of environmental conditions or soil life. In both of those cases, they are looking for moist but aerated shelter. To support your suggestion that many more gardeners follow your advice, I believe we would need many more local, carefully managed and coppiced woodlands to be created, which takes both land, time (to grow the trees), money and political will. Fossil fuels would be used to transport the relatively heavy woodchip vast distances. It should not contain large amounts of plastics, metals, and other contaminants. And unfortunately research cant be done for free. Also when ice forms in lakes and ponds over winter gas is trapped under the ice but has the chance to escape around the edges and holes. Wood chips look like a good natural intervention to address the gardeners weed problem and to enrich the soil life, but firstly we have to remember that this is not truly reflecting the local natural ecosystems. Were past the era of incantations, blood letting and humors. In areas where it was 1 plant per sq foot I mulched heavily w straw and had minimal weeds. The only way that any plant will survive that is if its attached to an underground rhizome system that supplies energy. I assumed they crawled out of the ground and under the wet cardboard. You also state: which is totally ignored by gardeners who are solely focused on crop yields. I recommend a soil test before you add anything else to your soil. Its thick enough to blocksunlight from reaching grass or weeds. Thanks! Doug Culver. Science is not something that is only accessible for lab coated technocrats. Furthermore, rototilling destroys soil structure. Yes, cardboard sheet mulch kills off perennial roots, but that is only a symptom of the damage its use inflicts on *all* soil biology. The triangulation of an answer from these studies with respect to cardboard is tenuous at best; I read them to indicate that straw may actually be the best mulch. So dont assume your lasagna mulching draws earthworms to your garden. I believe that certain worm species will do well with lasagna gardening and that anecdotal evidence is relevant due to the absence of scientific data either way. I am a terrible gardener b/c I dont like to kill anything but also a kind human. For a while I simply used heavy weight plastic bags that I would fill and refill as the contents broke down. I would like to see proponents of the method fund independent research to generate some direct evidence. Are you aware of anything scientific that shows cardboard is detrimental to plants or soil life? But cardboard is still a useful addition to a compost pile as a source of carbon no? Would they not act the same as what you think the card board is doing. I am an amateur gardener, with an Environmental Biology degree, who practices no dig in my garden (via Charles Dowding and similar professional gardeners advice). Thats why the diffusion coefficient is so important. Amazon boxes that are easy to tear and fall apart when damp means okay for the soil but for keeping weeds out, not so much. So Ive created a larger opening and placed extra native soil in which Ive planted the plant. https://www.nacaa.com/journal/index.php?jid=1024, It works! Click on the Information Link below to learn more! How long until the soil recovers? The garden is the perfect laboratory for experiencing science in real time. As Ive told others on this post, you are providing anecdotal evidence. CDFA California Department of Food and Agriculture. There is no published research demonstrating any beneficits to using cardboard sheets as a mulch so any discussion of it is anecdotal. Im sorry but I have seen soil and growing systems greatly improve following sheet mulching. The standard panel width is perfect, it can be found cheap, will last for years and its easy to cut. The cardboard seems a little gentler on the earth, and so much less stressful. Just now getting caught up. By importing woodchip from further afield Id be concerned about the embodied energy used in its supply. In recent years, Ive wanted to provide more native soil to plants. Its a great way to use invasive species for something useful. You need to be able to isolate the area from invasion at least until your desirable plants have successfully colonized the area. Really? I initially use cardboard mulching to suppress weeds (unwanted plants in my veg plot), with compost/well rotted manure placed on top, but generally I only use the cardboard in the first season, if the weeds are particularly pervasive. They need to establish into the site soil. Coarse mulch will prevent weeds and takes longer to decompose. The weakness in the approach is me being consistent with a busy work load distracting me elsewhere. Do you have a good article on those? I used this under a (formerly) permanent 8x8 bin with reasonable success. You all are getting bent out of shape because their beliefs were attacked and they cant handle the facts. I love your science-backed blog! Next, mow that stuff right down to the ground and then heap on the wood chips as deep as you can at least 6 but you can go even deeper if you have the chips. It isnt an option openly promoted in my area. Im going to put this idea in my back pocket just in case. I never water because it is very expensive. Kev Mans comment that Cardboard is made with non-toxic (usually fish-based) adhesives sounds very encouraging, and I hope this is actually true. I am considering using cardboard as much. Pete. This product is not available for purchase online. Ditto, to what Mike said. The conclusions are not borne out by the results, which are all over the place. He grows everything from vegetables and fruit trees to shrub roses and peonies, using only two ingredients: cardboard and compost. When laying on top of each other, as they compress and if damp, they are not as three dimensional as woodchip (i.e. I live in Michigan. It would take me all year to get them down. Yes, cardboard (shredded or otherwise cut up) is a good brown material for compost piles. We have run into the problem of Herbicides leaching out of compost brought in from a Horse Farm, Pig farm and/or purchased cottonseed but compost. Thank you! Thanks for your response. Now, is this better than a simple thick layer of chipsthat is for the scientists to figure out. Thats when the earthworms come to the surface. ), Thank you! Its spores can cause death in chickens. ), Dr. Chalker-Scott, the Master Composters at Clark County have build over 1,600 square feet of lasagna gardens using cardboard as a weed barrier. I do take the time to remove any tape or plastic labels from the boxes. Not true. Burlap and other open weave materials dont reduce light. Mike McGrath in one of his You Bet Your Garden podcasts mentioned a fungus that grows on/in/under wood mulch. Is that a good idea? Our peer-reviewed paper is currently in press. And you want to plant your plant into the soil not on top of cardboard. What is going on? Your soil system will recover from the tarp. You publish a graph showing CO2 diffusion rates through various media. Even shredded, cardboard is still going to act in a sheet-like manner. Also, I was wondering would hessian/burlap fabric be a good, more breathable alternative to cardboard as an organic material to smother vegetation and cut holes in to for new planting? Thanks for your time and interesting website! To specify to your own yard, use the materials calculator. Not enough for my total needs, but plenty to test with. Should I soak first and how long ? My apologies, I posted the incorrect link: https://projects.sare.org/project-reports/fne10-677/. She also is one of the Garden Professors a group of academic colleagues who educate and entertain through their blog and Facebook pages. What organisms died? I hope you wont mind me being specific. In fact the invertebrates are able to recolonize the cardboard wastelands relatively quickly; it is the complex soil biology that takes years to restore itself. Im not sure did you test damp cardboard vs. dry cardboard? I have very much enjoyed this post and the subsequent conversations. Hi Linda. This variable could have also been tested on a mesocosm scale, alongside the other mulches you used. We just bought a house that many of the plants were dying. Oxygen is THE limting factor as you travel downwards in soil, so anything that slows gas exchange will limit oxygen availability. That may seem like a good thing but the fact is that in the long run it has resulted in enormous damage to agricultural soils. So I cant address your question sorry. Ill try mulch, although a goat sounds fun. Do I have to install a weed barrier to prevent the rhizomes from running underground from adjacent grass to the piles? This is for a relatively short period (likely to be a few months) whilst the cardboard breaks down. It does not absorb water and will not contribute to soil building. August 5 2020: You state: There is no theoretical plant or soil science that would support the use of cardboard, so the additional lack of any practical published evidence means theres nothing that a scientist could use to support the use of cardboard, given the collateral damage imposed on the soil ecosystem (which is totally ignored by gardeners who are solely focused on crop yields). ^_~. Now, until cardboard proponents publish evidence to the contrary, its pretty obvious that cardboard mulch interferes with gas diffusion. They will not affect nitrogen. Cant it send its runners up through the thickest piles of park? What side of that do you want to be on? To be more clear, wood chips do not create dry and lifeless conditions underneath. Theres a limit on chip depth when planting. Then I was wondering about supply and demand. My apologies for the rambling. But plants seem to love it. It makes sense that lasagna mulching can help create an environment (temp and moisture) that will increase earthworm carrying capacity. It is not topsoil and it is not natural. While the soil may be moist, you dont have any idea what the oxygen levels were during this time and whether your soil life was affected negatively. However, the facts remain that cardboard is made to reduce both moisture and gas exchange, and that earthworms (as well as other soil organisms) need oxygen in the root zone. This year my project is building a retaining wall and filling in four feet high with fill dirt behind it. First, under what context is the rate of diffusion critical to soil or plant life? I found this article you recommend extremely helpful about use and application of woodchips and it seems to make a lot of sense to use woodchip in our gardens: What chemicals was that pallet wood treated with? You then go on to say that the woodchips are three dimensional. I have an 100 tree orchard in the desert and I wish to use an abundance of chipped and shredded cardboard to improve the soil. Do you just leave it at this point? I am guessing since its this thread it is the former and not the latter. The finished linerboard is laminated using adhesives to both sides of the fluting material. It comes up through just about anything. Weve now published research that shows cardboard significantly reduces gas transfer compared to wood chips. Thanks, Tanya, for taking the time to read the information with an open mind and think about it objectively. can be a great mulch. Is the lower-oxygen environment created by tarp/cardboard sufficient to produce these pathogens? Yes, this is what I did in previous yearsI laid down cutout patterns and mulched the entire area, then picked up the piece and there would be a small area uncovered by mulch that I would plant in. We initially sowed pasture grass on it just to occupy it, but because it essentially has no topsoil or organic matter has very little growing on it, except for some nasty weeds (Himalayan blackberry, bull thistle, tansy) and some grass. I have degrees in both Physics and Biology and have always been interested in philosophy of science. Soil oxygen is generally what limits the depth at which organisms can survive. I was wondering if the chemicals that are found in cardboard would also be a reason not to use cardboard for mulch. nematodes? This is the biggest obstacle of this system to me. Newspapers will restrict gas mavement as well. Have you ever actually tried this? The body of published evidence relevant to gardens and landscapes is not controversial to those of us who conduct and publish research. Just dont use it. All of these things, by their physical design, will restrict water and air movement. anecdotal) and limited, but remember that science itself is always fallible and that some of the most impactful studies were inspired by researchers experientially-drawn hunches (see for example Michael Polanyi on this point with respect to scientific epistemology). They have the added benefit of being really big. Thank you! In places that have the morning glories (bindweed) and Himalayan blackberry that Earthdave brought up, however, Id still consider whether to keep using cardboard. There are a number of misconceptions in this plan and I hope I can dissuade you of them. Weve migrated the blog a few times and sometimes the links dont get fixed. This limited the plant-based testing to qualitative results, as we did not have enough plants in reproducible conditions to generate sample sizes for statistically significant data. By far the most efficient are deep layers of coarse materal, which allows water and air movement but restricts light. https://www.farmprogress.com/vegetables/usda-narc-project-verifies-vermicompost-can-increase-yield-soil-health. Please do not generalise. Im with you on the fungi one of the gifts of cardboard and bark has been morels! I think hes a very good gardener and careful about how he conducts his tests. Correct? This would need to be translated and scrutinized as it goes completely against the current body of published work. Hi Linda, I dont know much about gardening. Be aware that there will still be weed seeds in the soil, so if you are planting anything yuo should retain mulch wherever you arent planting directly. ???? Cardboard will decompose, but oxygen is needed for the process. Or would I need to get someone at a university to do it for me? Hi Doug Cardboard is ten times worse than wood chips in this regard. Wow, I am super impressed by this thread and its responses! Nothing (control). Over time, weve converted over 8500 sq. Without light, you will have no seedlings surviving to reach the surface of a deep mulch. These greens combine with the browns of the cardboard to create sheets of humus as they break down together. The only way deep layers chips will not keep weeds out is if they are invading from adjacent, unmulched areas.