100 cubic yards of wood chip mulch: how to speed decomposition of all that carbon?

Not sure if this is the right place for this, but here goes. Admins, please feel free to relocate if there is a better forum for the topic.

After much deliberation and discussion, my wife and I have decided to cover a large chunk of our suburban property with woodchips. We figure ~5000 square feet, so we'll be getting about 100 cubic yards of woodchips to create a 6" layer. (We can get them delivered for free from a number of local landscaping/tree services and hopefully we won't get all 100 yards at once )

The place we intend on covering was previously inhabited by English Ivy and maple saplings. It is shaded by some neighbors trees and my grass/clover mixed planting has not come in as well there as it has in other areas. Right now it is mostly garlic mustard and pokeweed. In addition, it is the most uneven portion of the property so it seems ripe for this kind of treatment.

We should be getting the product of trimming operations and that means leaves and branches as well as trunk chippings, but I'm still concerned about the massive influx of Carbon.

What can I do to speed the decomposition of all of that carbon-based material into something that will support plants?

I'm already thinking that I may need a spreadsheet to keep track of where I'm peeing in the yard (Where else but a permaculture forum would you see a sentence like that?)

Would replanting the area with clover help after we put down the chips? Or would that be good money after bad?

Watch "back to eden" garden, but more importantly--search on youtube for the followup Q&A and garden tours. That is where the details that make/break the system are.

The carbon will only break down when/where it can get nitrogen, so that is just the surface of the old soil and what you put on top. It will not suck up all the nitrogen down to bedrock. It will probably absorb all you try to add on top (pee or clover) so it plan accordingly.

As the biology builds up, it will convert the carbon faster. So mulch will last forever on top of dead soil, but disappear quickly on healthy soil. Adding nitrogen is part of speeding it up, but so is compost tea and biology.

when you want to grow a specific plant in that area can't you push the mulch aside and put in plant or seeds and some compost and things if you want and then pull the mulch back if it is a plant or wait for a seed to sprout and then push mulch back?

R Scott wrote:Watch "back to eden" garden, but more importantly--search on youtube for the followup Q&A and garden tours. That is where the details that make/break the system are.

The carbon will only break down when/where it can get nitrogen, so that is just the surface of the old soil and what you put on top. It will not suck up all the nitrogen down to bedrock. It will probably absorb all you try to add on top (pee or clover) so it plan accordingly.

As the biology builds up, it will convert the carbon faster. So mulch will last forever on top of dead soil, but disappear quickly on healthy soil. Adding nitrogen is part of speeding it up, but so is compost tea and biology.

Thank you for the info. I did watch the 'Back to Eden' film, I will have to look for the follow-on videos. We don't have any plans to make this area a food plot of any kind as we are leaving the state in less than 5 years, but I would like to do something attractive and purposeful. I had been thinking of a few beds of pollinator-friendly natives with clover-filled paths around them. Maybe a small water feature for the birds, frogs, and other critters.

It did suddenly occur to me that there's a furry little nitrogen machine residing in our house right now: Buster the Bunny! Time to put him to work!!!

I'm just getting started on composting and I'll read up on compost tea.

What I do is get huge cardboards at the plumbers supply store. Put down a generous layer of cardboard, then a mulch (I have to pay for) and on the top of it I simply build my beds. It is called sheet mulching. You don't have to wait. I buy spent mushroom compost and pick up horse manure from a paddock.

These people did exactly what you plan to do! Check it out:


To speed up decomposition they spread mushroom spawn over the chips & added rock dust.

Another idea is to add newspaper on the bottom to shade things out, add compost on top of that, then add whatever soil additions you think are necessary (bone meal, urine, etc). Then, add mulch as the last layer on top. This is essentially the gist of "Bomb-Proof-Sheet-Mulching" that Toby Hemenway talks about in his book Gaia's Garden. I probably forgot a few steps in describing it. I highly advise reading his book; it is extremely informative. You could also add clover on top of the mulch if you feel that you'll need more nitrogen for decomposition.

I prefer cardboard to newspaper. Big sheets of cardboard.

Mushrooms mushrooms mushrooms! Colonize with types you love to eat, and they will break down the wood into components that bacteria can eat, which are consumed by flagellates, which create bio available nitrogen when they die. If you really want to get things going, spray liquid fish and black strap molasses on the mulch to give the fungus and bacteria a boost. Alternative to consumeable mushrooms, you can buy a root dip and mix with water, the one from Paul Stamets has 30 or so different mushroom types which help roots of plants and many are sapotrophic, or you could buy "effective microbes" or do compost teas. You have many options to help nature along.

Andrew beat me to it, but the only thing you need to add is fungi. Not that spores won't eventually find this bonanza of food, but any mushrooms that you add just gives it a head start.

Realize that once you spread it out and it starts getting rained on and decomposing, you soon will have 3" instead of 6".

I wouldn't replant the area with clover. If your climate is mild enough, you may be able to do the Southern trick of sowing crimson clover in the fall as a cover crop and let it build nitrogen in the soil over the winter. But we generally seed crimson clover around October, not now.

With 6" of mulch, you probably have enough suppression of weeds that you can dispense with laying down sheets of cardboard first. And if you do want to plant, you can plant directly into the wood chips IF you put some topsoil on top of the chips around the plant to keep them from drying out -- kind of a reverse mulching. I find that the intense summer sun here in Georgia can dry out the top few inches of wood chips, but not with an inch of topsoil to hold in the moisture. I've done that with sweet potato slips, marigolds, lemongrass, and other transplants, and it seems to work well.

If you get your chips from deciduous trees during the spring or summer, your chips will decompose much faster (with green leaves) than in the fall or winter (without green leaves).

Don't underestimate the amount of labor required to move 100 yards of wood chips. I got 40 yards of chips delivered in 2 days. Moving them all to the backyard was not real fun.

As others have stated, once the conditions are right, you will be living in fungi city . Although my 40 yard pile also has a lot of "dog vomit slime mold". Yes that is a real thing

I too would skip the newspaper/cardboard unless your plants are super aggressive. Personally I prefer newspaper to cardboard. The Wall Street Journal is may favorite because it isn't full of slick inserts.

We used massive quantities of wood chips on our property in Wisconsin. You can put them down thick wherever you don't like what is there. If what is there is particularly invasive (and ivy might qualify), it helps to put down a solid sheet of something (newsprint/cardboard) over the unwanted plants and then pile on the wood chips. To plant a desired thing (ideally after you've waited months for the unwanted plants to decompose) you just dig down through the mulch to good soil. Obviously, you have to cut through the cardboard if it is under there.

When we moved in, the east side yard was narrow and shaded and the lawn was poor quality. Then, we put in a fence (for the back yard) and it became hard to reach with a mower. I just buried the whole thing in wood chips and over the years that became a lovely shade garden. Another unwanted bit of lawn was almost completely surrounded by shrubbery. That was in full sun and I buried it deep. The mulch held as a place holder until I could figure out what I wanted there. If you do nothing but pile on mulch, at least it looks OK. If you plant in some nice blueberries (or something) then it will look rather nice.

Moving wood chips via wheelbarrow is a lot of work, but it's good exercise and you get that instant gratification of seeing things change. If you have a garden cart it's not quite as exhausting (the weight is born by the wheels and you are balancing it and providing forward motion) as a wheelbarrow. Of course, if you have one of those cool chinese wheelbarrows with the wheel in the middle, well, then you don't need a garden cart. The wheelbarrow is best for controlled tipping - I had one that actually had a sort of spout at the front.

It sounds like you have a large property and will use the mulch to get a troublesome area under some control. That's an excellent strategy. Over time the wood will break down, whether you do anything to it or not. When it breaks down it makes the most amazing soil, just like in the video above.

First off: water every day, either in the morning or evening. Nothing, bacteria or fungus, is going to go to work on those chips while they are dry.

Let me add my two cents and give another vote to mushrooms. Sounds like your situation calls for spore broth. Look up "spore broth" on google and you will be fascinated. I highly recommend you inoculate with some edible, saprotrophic mushroom spores.

Popular candidates are: oysters, shitake, lions mane, reishi and a few others.

Personally, I would go on a mushrrom hunting foray and look for some local stuff. For instance, if i were to do this in the PNW, I would use: shaggy mane, shaggy parasol, prince, blewit, angel wings (perfectly safe in reasonable quantities, but you are free to disagree) or scotch bonnet (fairy ring mushroom). I'd make a new batch of broth every time i came back from a trip. You would end up with a wonderful mushroom polyculture that would break down those wood chips with or without added nitrogen.

I like the cardboard, because it does attract mushrooms.
For the spore broth do you use shop bought mushrooms? The only edible mushrooms round here I know are slippery jack and saffron milkcaps and they only
grow under pine trees.

Angelika Maier wrote:I like the cardboard, because it does attract mushrooms.
For the spore broth do you use shop bought mushrooms? The only edible mushrooms round here I know are slippery jack and saffron milkcaps and they only
grow under pine trees.

Keep in mind, i am speaking from armchair theory. I read two of Staments books but i haven't had the chance to get to work on my farm (still waiting for the wives visa application approval before we can move to Washington).

Local mushrooms are better adapted to your local micro fauna and are more likely to be successful. That being said, there is no reason you cant buy some mushrooms from the store (the fresher the better) and use those to make some spawn or spore broth.

Furthermore, because its cost prohibitive to buy enough mushrooms to make the quantity of spore broth one would need for so many wood chips, keep in mind that the broth can be expanded 10x each generation. That means that after brewing 5 gallons for 48 hours, you can use that broth to brew 50 gallons and after another 48 hours to brew 500 gallons and on and on. There is a limited number of times you can do this before the mycelium starts to weaken from genetic inbreeding. I don't know how many generations you can do like this. You would have to look it up yourself.

Thanks for continuing to feed me suggestions and ideas!!!

We have kinda settled on turning the area into a semi-naturalized spot. Possibly with a small water feature, probably with a couple of benches for sitting in the shade, definitely with native plants that are pollinator and wildlife friendly.

Notes:

1) Yes, the thought of moving 100 yards of woodchips doesn't exactly thrill me. The thought of having the area overrun by whatever gets blown in or pooped out onto it thrills me even less. Especially after I spent so much time and energy getting rid of all the ivy and maple saplings. Hopefully, I can get the deliveries spaced out over the summer and not end up with a broken back & a front yard full of woodchip piles Most of the tree services and landscapers around here use trucks that are 15 yards and under, so a delivery every other week should keep me busy without killing my enthusiasm for the project.

2) The mushroom concept really intrigues me, but I have concerns and questions. If I were to inoculate the whole area with a cocktail of mushroom spores, will they impede the other plantings? Is the whole place just going to look like some bad SyFy channel movie? "Shroompocalypse"?

3) Cardboard & newsprint will probably be put down for the errant ivy sprout, but I am concerned here as well. I have managed to get 2 compost piles up and running (#3 is in progress), but when I turn them I see gazillions of earwigs. Won't they love the cardboard & paper even more than the worms?

4) The clover I tried previously was white Dutch dwarf clover. I used that seed because it is available in bulk from the Long Island Cauliflower Association (Yes, that's a real thing. Surprised me, too ). Also, it's something I like to see in the lawn. I will probably seed more of it on the lawn areas and the woodchips as well, depending on finances.

5) I'm also thinking of throwing in a couple of semi-Hugels closer to the back fence and topping them with a native mix of seeds including Big & Little Bluestem. I'm hoping that the Hugels will give some extra height to the Bluestems and act as a living privacy fence.

Hugels are great as a privacy "fence" by a road because a berm really stops sound. So, go for it, and build them as high as you dare - they will settle down with time.

Don't worry about earwigs. I mean, they eat lettuce seedlings so they are annoying, and they just look horrible, but they're not toxic or dangerous. Chickens will eat them. They live on decaying plant matter, I think. When we were at an insect museum in New Orleans, they had a giant animated female earwig, standing over her eggs with that crazy tail curled over her back like a scorpion. They said that earwigs are good mothers and guard their young. That blew my mind. I still squoosh them in the house, though!

If you are working on a large property, the time that unamended wood chips gives you is valuable. Thus, I wouldn't spend time or energy on cultivating mushrooms. I did add Winecap Stropharia spawn to my thickest bed of wood chips after it had been there a decade (and had been topped up a few times) and then I had edible mushroom popping up, which was cool, but you can do that later.

There are only a few mushrooms that select for certain plants (and kill others). The delicious Honey Mushroom kills some plants, but no one really cultivates it as far as I know. Most are incredibly beneficial to your situation. The recommendation to wait is fine, you can wait as long as you want. However, mushroom mycelia break down the wood chips into useable soil. Inoculation with beneficial mushrooms will slow down other types of mushroom which may not necessarily be beneficial. Additionally, some mushrooms bind to the roots of your plants and trade minerals and water for sugar. Mushrooms extend the plant root zone in these relationships by logarithmic factors. A single cubic centimeter of mushroom mycelia may contain yards and yards of filament (hyphae). The place to find these types of beneficial mushrooms in the quantity needed to inoculate such a large area are in a fungal Root Dip innoculant, like MycoGrow, or in compost tea. My favorite compost tea is made with vermicompost and black strap molasses aerated to very high O2 concentration over 24 hours. Apply either product before rain for maximum effectiveness. As I said before, maintain biological activity with liquid fish and black strap molasses, if you really want to get things going. Just spray with water once in awhile, and the biological activity will be enough to make your plants happy. There will be no Shroompocalypse, the opposite should be true.

Frank Brentwood wrote:Thanks for continuing to feed me suggestions and ideas!!!

We have kinda settled on turning the area into a semi-naturalized spot. Possibly with a small water feature, probably with a couple of benches for sitting in the shade, definitely with native plants that are pollinator and wildlife friendly.


2) The mushroom concept really intrigues me, but I have concerns and questions. If I were to inoculate the whole area with a cocktail of mushroom spores, will they impede the other plantings? Is the whole place just going to look like some bad SyFy channel movie? "Shroompocalypse"?

mushrooms dont compete with plants. They eat different things. Saprotrophic mycelium eat wood chips while plants use much more simple elements to fuel growth (mainly NPK). It is almost like comparing a human with a tree. Trees cant eat steak and potatoes while humans can't eat nitrogen. Then again, we DO eat nitrates in our sausages but that usually leads to colon cancer.

Thanks again to everyone for the info and advice! I have SO much to learn and even more to DO.

New things to incorporate into the "plan":

1) Hugels make good neighbors
2) MycoGrow for a first blast of shroomy goodness.
3) Liquid fish & black strap molasses go onto the shopping list.

New questions:

1) I read somewhere that using native mushrooms to inoculate is best. Knowing as little about shrooms as I do, would it be beneficial for me to take a wander through the woods and gather a bagful to put through a blender and spread over my woodchips? Obviously not for eating, but just to propagate regionally adapted species. Am I over-thinking this?

2) Along the lines of liquid fish & black strap molasses, are any of these internet concoctions any use? The ones that put a can of beer, a can of cola, & a cup of ammonia into a hose-end sprayer and hose down the lawn/garden/compost pile/whatever.

Take a couple small samples from the woods. Maybe a small shovel full for each tree species. Conifers are especially good sources. Keep them separated if you want to propagate the fungi/bacteria/organisms later.

There are different types of fungi. Some fungi helps plants get nutrients, and requires to grow on the roots of plants. Some plants just break down organic material and don't help/grow on plant roots. In the forest, there will be a mix of these. For your plants you want the helpful fungi. For your wood chip processing you want the general ones. Without plant roots the symbiotic fungi would just die.

I would collect the soil and keep out of sunlight the entire time. UV radiation can kill a lot of soil organisms. Apply it to the hole when you plant your plants. Taking parts of the soil and extending it with compost tea will be the cost effective and least impact on the soil in the woods. Once the plants are growing, they will spread the fungi to new plantings. Disturbing the fungi will destroy them.

Liquid Fish Emulsion will activate a lot of organisms and I find incredible fungi development with it. Urine works pretty well too. Molasses will attract too many things to be used I think.

Would suggest reading "Teaming with Microbes", has a lot of the details you're looking for with the relational aspects of the microbes.

You will be happy with local mushroom sources, except if you innoculate with Honey Mushrooms. Be careful, they spread quickly, they parasitize many useful tree species while the trees are alive, kill them, then eat up the woody remains. There is a colony of honey mushrooms in the Upper Peninsula of Michigan which is reported to be larger than "Pando". Pando is the single Populus (aspen) tree stand with the same roots which for a time was the largest organism on earth. This honey mushroom colony is something like 3 sq miles.

For the local 'shrooms, the soil under conifers and pines is nice for extending the roots of your plants, but other pine/conifer mushrooms produce "brown rot" when they are saprotrophic and eat your wood chips. Brown rot selects for conifer and pine species and associates. Under hardwoods, you'll find "white rot" species, which do not really select for certain types of trees or plants, or at least should not trouble any food crop.

Actually, now that I think of it. Brown rots will only survive on pine and conifer wood food. You shouldn't have a problem with them if you have sufficient hardwood chips in the mix regardless of what you inoculate with.

Andrew Mateskon wrote: if you innoculate with Honey Mushrooms. Be careful, they spread quickly, they parasitize many useful tree species while the trees are alive, kill them, then eat up the woody remains.

Your going to give the poor guy nightmares! hahaha

Just dont go digging up soil in forests where honey mushrooms are present any you will be fine. No need to worry about killing your garden with a few shovel fulls of bad dirt.

I'm getting some mushroom compost from a local outfit to go on some wood chip piles and areas I want to build up as hugel beds to turn into good soil. What else is needed to help it rapidly break down? Have read rock dust, but with our alkaline soil and shallow topsoil till you get to limestone rock, may not be the best.

Cal, your conditions sound exactly like mine. In our walkways where we do nothing grass starts sprout in a little under a year. In beds where we actually want the plants sprouting we've been adding loads of manure and burying kitchen waste to compost in the wood chips. Biggest thing is keeping the chips moist so some form of life (bacterial or fungal) can grow within it.

The mushrooms will only come in where the conditions are right, so even if you were able to inoculate the entire property, they would appear in their "sweet spots". I've struggled for years to get edible mushrooms going, they don't seem to like where I think they should...

DON'T use liquid ammonia as a N source, complete waste of money. Get urea prills or ammonium sulfate if you are intent on adding N. Wood chips have a low pH, and ammonium sulfate will drive it lower as it reacts, perfect for blueberries, not so much for everything else. Are you looking for plants to grow IN the chips, or under them? If you are planting in the soil underneath, there's no need to do anything to the chips. I've got grass growing in wood chips that have only been down for a year, and it is not N-deficient.

Earwigs can get WAY out of control if they don't have enough predators. I've had literally thousands climbing the exterior walls here at night. I put out short cans of used cooking oil, which they commit suicide in, and when they are full, I give them to the chickens. Yum, oily earwigs! The earwigs tend to really take off in March around here. If you do a water feature, be sure to add some tadpoles to get a local predator population going. Earwigs are nocturnal, like toads. Chickens and wood chips don't mix, if you care about looks. They will dig holes everywhere.

I read about a composting operation in Mexico, their main input was wood debris. The intent was to make compost that was suppressive for fungal pathogens, which is why I was interested. Here was their recipe/protocol:

- hardwood bark, fine
- .66 lbs N per 1.3 yds or 10-20% grass clippings or 10-15% chicken manure
- inoculate after peak heating
- min. 6 weeks til mature.

I had to convert from metric, hence the 1.3 yards... Note that they used bark in their final product, might make a significant difference. I used wood chips when I tried it, it certainly got hot. It seemed to reduce the fusarium that crops up every year here. I used MycroGrow as the inoculant, BTW.

Don't have chickens at the moment. Will be using the wood chips to build up the soil with the intention to plant into them as they break down. As far as inoculant, as it will be a large area looking for the cheapest route to go to encourage that.

Add coffee grounds free from any coffee shop just leave a trash can or other large container. Use spent brewers grains free from local microbreweries. Horse manure is often available free as well just make sure the horses had not recently ingested a deworming agent.

Cal Burns wrote:I'm getting some mushroom compost from a local outfit to go on some wood chip piles and areas I want to build up as hugel beds to turn into good soil. What else is needed to help it rapidly break down? Have read rock dust, but with our alkaline soil and shallow topsoil till you get to limestone rock, may not be the best.

What time frame are you talking about when you say "rapidly break down"? Wood, chips or otherwise, is not your first choice for rapid composting, as in the Berkeley method that hot composts in 18 days. That is a bacteria system, but bacteria cannot break down lignin, it takes fungi to do that and they work more slowly.

Classic cheap source of nitrogen is urine. Dilute with water about ten to one. Hugel beds are not fast systems, they take time to develop and that is part of the point, they are slower both building and fading away. Sepp uses them as a method of creating good soil over time from material that would otherwise be a disposal problem.

What time frame are you talking about when you say "rapidly break down"? Talking about a year or more.