where mulch ends and compost begins

Just curious what you guys are up to and how you're seeing things. For me we have a lot of wood chips, and have observed a few things.

Raw wood chips either get put onto cardboard with rock edging for paths, or it gets left out to get it less "fresh". Our wood chips are 90% conifer so I like to wait for the pine oil stink to wear off if I'm going to use it on the ground for plants.

But there's a wood chip pile over the summer that I've been putting table scraps and the such into, and there are now nice black/warm sections breaking down.

Likewise for the woodchips I put on the ground I'll put blood meal (super high nitrogen) on to hopefully break down all the carbon in the mulch.

So yeah like I said, just wondering where you guys see mulch vs compost since one eventually becomes the other.

I'm still learning my way around woodchip mulch and also spoiled hay. And I don't really think too much about the dichotomy making the two (mulch and compost) distinct. I planted this year into hay and chips instead of soil. Potatoes like growing on top of the ground, but under hay. Nothing grew well in thick wood chips. But that's OK, it'll break down. And where I pulled the chips away and planted a row of stuff, it grew just fine. Where the chips aren't super-thick, sheep sorrel and one of my grasses seem really happy to fill in all the gaps. I have little piles of chips all around the property, because I've been using them to smother thistle and burdock, just to see how much is needed. It's adding texture and edge to the property and again, it'll break down into humus, given time.

I am similar in thought to you but my process is a bit different.

I compost separately from my chip piles because I currently use the chip everywhere.

My current intention (Still being proven out) is to lay fresh chip in my garden paths, chicken run, and used to delineate some lines in my lawn along a slope.

While I have gardened this year, I pull weeds/trim plants/bad fruit I will toss it on top of the garden path to let it intermingle and combine together. I also have introduced mushroom spawn into the chips and let it take hold.

This following spring, I'm going to scrape back the top layer and dig up what I'm hoping to be semi/fully processed woodchip material and use it for my beds/plantings. Then I will put on a new layer of chip and rinse and repeat.

One hampering problem is the fact that I have asian jumping worms on the edges of my garden path. I'm not sure what effect if any they will have besides having to worry about egg cocoons. If I can isolate them, I might experiment on what works to kill them that might be least impactful to the rest of the environment.

Timothy Norton wrote:One hampering problem is the fact that I have asian jumping worms on the edges of my garden path. I'm not sure what effect if any they will have besides having to worry about egg cocoons.

I've heard of them, but no nothing about them. Would a chicken tractor you can park over the paths help in some way?

Unfortunately, there is a study that seems to indicate that they bioaccumulate heavy metals to the point that there are indications it might be effecting wild bird populations. I have read a few people do utilize chickens but I'm holding off until there are more studies done.

Timothy Norton wrote:Unfortunately, there is a study that seems to indicate that they bioaccumulate heavy metals to the point that there are indications it might be effecting wild bird populations. I have read a few people do utilize chickens but I'm holding off until there are more studies done.

Not sure if this is the one you're talking about, but it was an interesting read: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3447579/ . Some takeaways I noticed are (a) it's for fairly large scale operations, not a dozen birds like most people on here might be dealing with And (b) a lot of it is traced back to the feed they're getting. They're talking about chemical elements, and those can't be synthesized from anything. Like arsenic can only come from arsenic so if it's not going into them, it's not coming out of them.

I occurs to me that stone and plastic count as mulch.
While they do decay, they are pretty terrible compost.

No judgment here, but loads of plastic seems to be key to no till/no spray commercial operations.
I am interested in basalt fiber fabric  as an alternative, but I don't have the funds to try it out.

I do have an unlimited supply of tile, which I'm looking at for its weed suppressive possibilities.
I have a yellowhorn tree that can't seem to compete with the plants around it, especially poison ivy, so maybe I'll  mulch it with tiles.
I tried flat stones but the gaps in between them are too large.


One really weird idea I had was petrified hessian or burlap-crete.
It wouldn't last forever, but it should offer great protection, and eventually it would return to the soil.

Gravel makes a great mulch. The weeds in our driveway always look great. 😂

This year I ended up adding most of my food scraps to my beds before topping with fresh compost. Most other stuff just got chopped and dropped. Did a vaguely keyhole garden thing with ring of tomatoes. Add any of my kitchen scraps on top and then cover with more straw, corn husks, etc. Definitely compost and mulch at the same time.

Just adding my thoughts….. I’d really wish I had access to lots of waste wool. I’d like to make crude felt and try using it as weedblock/mulch.

Wood chips mulch is alien to me.
I don't have a wood chipper, and I cannot afford purchasing the chips. Even then, I am not sure that mulching with wood chips works in my place.

Wood needs funghi to decompose. Funghi need constant humidity and remain undisturbed. Constant humidity is something I don't have and cannot provide.
As I have observed, little branches that remain on the ground are just oxydized by the sun, in what looks to me as a low temperature burning. When the process is over, only ashes remain. Larger branches just remain there as dissicated trophies.

I think the only way to decompose wood in these conditions is to bury them deep enough that they keep moisture for a few months, but not so deep that microbes can't reach. I am also trying to decompose shredded paper in the composting bin, since it holds water much better than the pile or the bath tube. Theoretically, that would work for wood chips too, but I prefer the shredded paper, as it looks ugly. Leaving small branches over the place just makes the place look neglected, but using shredded paper as mulch is ugly, so off to the composting bin they go.

Then there's Charles Dowding's No-Dig Gardening style, which uses compost AS the mulch. Being in a wet UK climate, he says he'd have big slug problems if he used wood chips or other undecomposed materials as mulch.

I live in a dry climate and am gardening on land that was empty desert, so I'm greedy for any biomass I can get. Wood chipping is not a thing here: people use even thin sticks for fuel.

I have mulched with the wood scraps leftover from construction (the sawdust and shavings went into the composting toilet): It looks like garbage and breaks down very slowly, but it was helpful when I had no other mulch material in this desert.

Then I also collect mulch materials from anywhere I can: I get somebody in the nearby village to give me his autumn leaves that he'd otherwise burn.

I go and cut mulch from a huge stand of perennial pepperweed (Lepidium latifolium, invasive in US but native where I am) that is growing vigorously along the river; I cut it green in June before it flowers and sets seeds, for mulch that will quickly decompose, and I cut it in winter for stiff white stalks that look good for a season and eventually compost right down the second or third year.

And as my trees grow in, I cut up prunings for pea trellis and mulch; I'm crown-lifting the willow and russian olive, so there are lots of tender long shoots from around the lower half that I can easily snip with pruners into a sort of woody hay that will last a few years.

Su Ba wrote:Just adding my thoughts….. I’d really wish I had access to lots of waste wool. I’d like to make crude felt and try using it as weedblock/mulch.

Just came across this post while looking for a 'waste wool' thread.  You don't need to felt it...the rain will do that for you. :)

I save all my waste wool and lay it down about four inches thick (a fluffy white mat) in the fall before the rains start.  The rain and cold mats it down and by late winter it is a great weedblock mat.

Great thread. I think that how organic mulches turn into compost is one of the many reasons they are infinitely better than plastic.

I have spread a lot of woodchips (hundreds of yards) on my gardens and food forests, but seems like soil microbiologists (James White, Elaine Ingham, many others I have read or heard on podcasts) are getting more and more evidence that the best mulch is a living plant. All plants produce exudates to feed microbes which in return provide plant available nutrients. At least 30% of all plant sugars produced go to microbes, with up to 50% seasonally. When we chop and drop a weed, the greens provide shade and food for microbes, and the roots decompose and leave corridors of compost for future roots of plants we want to grow.

So I have come to only pull weeds when seeding or planting starts, with the exception of really aggressive spreaders like grasses, ivy and mint which I do try to get roots and all. Otherwise, everything just gets cut back with my brush cutter in late spring just before fire season. I use a sickle for right around trees and plants I want to keep.  I leave most of it on the ground, ideally covering planting bed soil. I do move some to compost piles because piles of drying cut grass upwind in fire weather is a risk to our house.

If I have bare ground in the winter for some reason, I will mulch with woodchips. I also use them in my sunken pathways between hugel beds. If a have a future garden or tree planting spot that has minimal soil to grow plants to get the soil sugar pump primed in the first place, I will spread woodchips to decompose and build organic matter. I use woodchips or woody debris around trees to get soil fungi a boost, but have leaned into spreading it less and piling it more since reading Michael Phillips’ “Holistic Orchard.” I have seen enough benefit and little perceptible harm in using conifer that I don’t worry too
much about it, but I will take all the alder I can get.

I think rocks make sense in very dry climates. Both plants and rocks help provide much more surface area for dew formation. If woody debris is broken down below 1ft/30cm, it generally gets enough soil contact to stay moist enough in the wet season here to inoculate with fire retardant fungi. In really dry climates though, it may just oxidize like was mentioned in a post above. Crushing this organic matter to the ground or eating it and depositing it as manure that then gets spread by smaller animals is a big reason why large herbivores moving frequently are so important to savanna and prairie ecosystems, and are essential to preventing their desertification.

Here is a photo illustrating what Ben just described. These are pinto beans about one month after planting.



The side with reduced growth was where the wood chips were piled for several months prior to spreading. On the left is the area that had been left to fallow and had a pretty wicked infestation of buttercup that got weeded with a scuffle hoe immediately before the beans were sown.