Mulch Mountain II: PU

by Daisy

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Just when the original mulch mountain was starting to look less mountainous, along came its successor: Mulch Mountain II.

I drove by a tree trimmer doing work in the neighborhood and stopped to see if he wanted to get rid of a few chips. Soon after, this is what happened:


“It’s a LOT,” he said. “Are you sure you want it?”

I was sure.

“It’s a whole lot.”

After much reassuring I knew what I was in for, the driver emptied out the truck.


Before he left, I told him there was room for one more load if he had it, so there may be MMIII.


There is a problem, a suburban problem.

It smells.


I had this issue with MMI, so I knew to expect it, but it does bear discussion.  The smell changes over time, but right now, a couple of days in, it has a sickly sweet and pervasive odor which, depending on the way the wind is blowing, can carry pretty far.  Neighbors or passersby might connect the smell to the chickens which of course is erroneous, but understandable.

The mulch pile isn’t visible from the road and plus, who knows what a decomposing pile of wood chips smells like? I didn’t have any idea myself before I had my own mountains of mulch.

As I remember from the first time, this lasts a couple of weeks.  There’s a quick build up at the beginning where it is stankEE. Then the level of phew gradually goes down until you have to be digging in it to smell it. It never gets so bad I can’t stand to be in the yard, however.

I’ve thought of putting a tarp over it, but I’m not sure that would help, and it might prolong the problem.

Suggestions are welcome.

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{ 17 comments… read them below or add one }

Deborah September 27, 2013 at 8:49 am

Be sure you let it thoroughly decompose before putting it on the garden. I made the mistake of using freshly cut wood chips on my garden one time. It killed everything and I had to start over.

Cinnamon Vogue September 27, 2013 at 9:11 am

I wonder if you can spray something on it to make it smell better. From previous discussion on this topic especially after MM1 I know you can’t bury it underground. At least that is what is what I undeerstood. Burn 10%?

Jeff Atnip September 27, 2013 at 9:55 am

Have fun with it. Walk around the yard in a hazmat suit and wave to the neighbors.

Mike Corbeil September 27, 2013 at 6:09 pm

Contact mulch experts:

I can’t answer your question, but perhaps you can contact the people of and successfully obtain all of the information you and others who wish to use mulching need to know. They’ll surely be able to answer your question and the only question that remains is whether they will, or not. I’m assuming that they will, and if they do, then I’d surely be confident about what they say. These people working this farm or farmette, unless it’s a garden, in the state of Washington certainly seem to be experts about the use of mulching. They love wood chips and evidently have made fantastic use of this farming/gardening method.

Full documentary:

These are just some extra notes.

The website provides visitors the ability to watch the full film of 103 minutes for free, online, as well as for purchasing the DVD. I viewed the whole film and it’s great; just that people who listen to it need to be tolerant about innocent (also amusing, without meaning this sarcastically) references to God when it comes to nature, hence “Creation”. Anyone who can tolerate a few such religious references should be able to greatly enjoy or appreciate this film.

The FAQ page:

I believe that when I first visited the website 2 or 3 years ago there was an easy, up-front way (link) to get to the FAQ page and I’m not finding this now. Doing a Web search of the website using FAQ for search term turns up the link.

The answers to the questions are provided in both text and video formats. It isn’t many questions and your question isn’t one of them, but it’s a page certainly worth visiting.

Mike Corbeil September 27, 2013 at 6:56 pm

I forgot to include a link for another resource that may, or not, be useful for your question. What the article says seems to be fitting though, and the link came up with my Web search using mulch and odor for search terms.

“Cornell gardening resources
Beware of toxic mulch”

Mulching is a great way to suppress weeds and conserve moisture. But toxic liquids and gasses can form in improperly prepared or stored wood-chip and bark mulch.

The best way to prevent this problem is to smell your mulch before applying it. If it has a pungent odor similar to vinegar, rotten eggs or silage, don’t spread it around your plants. Chances are good you’ve got “toxic” or “sour” mulch.

If the mulch smells like freshly cut wood or fertile garden compost, chances are slim that it will be a problem.

The toxins in sour mulch dissipate rapidly. If your smell test leads you to suspect a problem, spread the mulch out in a shallow layer for a few days on a driveway, tarp, or other place where it won’t damage plants. Exposure to air will usually get rid of the gaseous toxins. If the weather is dry, you can water the pile to leach out liquid toxins.

Have your mulch delivered well ahead of when you need it so that you don’t have to rush to apply mulch that could benefit from a few days or weeks of curing.

Sour mulch problems usually start where the mulch is made. Wood chips should be stored in long, low (4- to 6-foot tall) windrows and should be turned frequently. If they aren’t, pockets in the center of the pile may not get enough oxygen. The mulch may become laden with toxic byproducts such as methanol, acetic acid, ammonia and hydrogen sulfide gas. The mulch may also become very acidic, with a pH in the range of 1.8 to 3.6. (Properly composted organic material has a near-neutral pH of 6.0 to 7.2.)

Toxic mulch problems are not limited to commercial sources. Large piles of chips from storm damage clean-up or other tree trimming can also develop sour pockets. Again, the remedy is to turn the pile and expose the sour mulch to air and rain.

End quote

Another resource link:

“Control of Nuisance and Detrimental Molds (Fungi) in Mulches and Composts”, Ohio State U.,


The pH or acidity of the mulch is another important factor. Sour mulches that give off acrid odors may range in pH from as low as 2.5 up to 4.8. Highly acidic mulches are toxic to most plants and promote the growth of fungi. Bacteria that inhibit fungal growth cannot colonize mulches when the pH is lower than 5.2. The low pH and fungal problems are avoided if the raw material is nitrified and composted as described earlier.

End quote

I haven’t a clue if the latter article is at all useful, but the purpose of nitrification (if that’s the right word) of the mulch seems like it might be useful to you. I didn’t read absolutely every word of the article or factsheet, but read enough to see that it’s definitely interesting information for anyone practicing farming, farmette’ing or gardening with the use of mulch materials; some of them anyway. Bacteria vs fungii, the former beneficially reducing the harmful latter, nitrogen, ….

Teresa Melton September 28, 2013 at 7:51 am

I did that once but immediately spread it so it never smelled. I was going for the four inch effect and when I wanted to plant something I just pulled it back so it was just a benefit not a problem. Wish I could afford a few loads now at this place. I have mud…

Marco Polo Antonio September 28, 2013 at 4:08 pm

The chipped/shredded remains of my Honey-Locust, at my request, were left on my concrete driveway in a suburban neighborhood. During the next week the pile self-composted. Dry bark and moist chipped wood made the pile-interior almost too hot to touch; a column of steam rising each fall morning. Moved it out back and used it during the next three weeks. No problems.

Daisy September 29, 2013 at 5:48 am

Mike Corbell== Very good resources. Thank you. The pile does need to be turned. Since I don’t have the earth-moving equipment for that, I will probably do what I can in terms of spreading it out more so the air and rain mentioned in the article can get to it better. It may take it longer to compost that way, but it will compost eventually, and hopefully in a less odorous manner. I also appreciate the reminder of the Back to Eden people. Thanks for your time and help.

Daisy September 29, 2013 at 5:49 am

Teresa Melton–Mine was free, just have to catch them at the right time in the neighborhood.

Daisy September 29, 2013 at 5:55 am

CV–I don’t know of anything to put on it that wouldn’t alter the eventual compost. This is a no burn area, otherwise a bonfire sounds good!

Daisy September 29, 2013 at 5:55 am

Deborah–Sorry about your garden! How disappointing. I will wait.

Daisy September 29, 2013 at 5:56 am

Marco Polo Antonio–That was fast!

margaret September 29, 2013 at 11:27 am

well cover it with tarp and it will work faster at breaking down the rotting and it will get very hot under tarp and be better for you and the smell thank you i did it also so but didn”t have smell long

Mike Corbeil September 30, 2013 at 12:11 am


Regarding your response, “Mike Corbell== Very good resources. … I also appreciate the reminder of the Back to Eden people”.

It’s a great documentary or film. I’m not sure if it’s a farm, but the website refers to it as gardens (plural) and orchards (also plural) and this seems farm-like enough to me; just that perhaps the owners also derive income through other means.

A problem with most of the user comments, here, is lack of sources. Only juniors communicate in such manners, when providing no credentials or source references or links. They can still be right, but figuring out whether they are, or not, requires plenty of researching for the information or opinions provided.

But you added, “The pile does need to be turned. Since I don’t have the earth-moving equipment for that, I will probably do what I can in terms of spreading it out more so the air and rain mentioned in the article can get to it better”.

If it’s possible for you in the future to have the wood chips deposited in a more spread-out manner, rather than in a smaller (in terms of diameter) and very thick pile, then it’d save you the extra step of needing to spread out the pile. If you lack space for this, then maybe there’s some nearby land where you could have the chips deposited in thinner layers, after which you could transfer this “stuff” on an as needed basis to your garden. That would permit other people to steal your wood chips, but maybe it’d be safe enough.

Sarah September 30, 2013 at 9:46 am

You might want to look into using a product called EM-1 to help break this down and remove toxic gases from it. I use it in my garden, and have used it for stationary composting (no turning) and got great results. Here’s a page on their website about it:

Daisy October 2, 2013 at 5:11 am

Mike Corbeil–(Sorry, I see the “i” now.) I will try and have them spread it out next time, and maybe try Sarah’s suggestion of a fermenter to accelerate the process.

Daisy October 2, 2013 at 5:12 am

margaret–Glad to hear yours didn’t smell that long. I think mine might be getting better as the days go on.

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