Toxic Mulch

Discussion in 'Gardening & Plant Propagation' started by SueD, Mar 10, 2004.

  1. SueD

    SueD Well-Known Member

    Aug 1, 2002
    This is the same article I posted under Homesteading Questions... THought it belonged here as well....

    Today I'd like to share with you an article about a
    problem with mulch that few people are aware of. By making
    you aware I hope I can save you the aggravation that others
    have suffered.

    Beware of Toxic Mulch
    by Michael J. McGroarty

    Mulching beds has become extremely popular these days, and
    mulch can be really beneficial to your plants and the soil in
    your planting beds, but there are things you need to watch for.

    Here in Ohio the most popular type of mulch that people use
    is shredded hardwood bark mulch, which is a by product of
    the timber industry. When they haul the logs into the sawmill
    the first thing they do is debark them. Years ago the bark was
    a huge problem for the mills because there didn't seem to be
    a useful purpose for it, until people realized the hidden
    benefits that it held.

    Still to this day, the bark is a headache for the saw mills, and
    they don't always understand how to properly handle it. They
    like to pile it as high as they can so it takes up less space in
    their yard. The mulch really tends to back up during the winter
    months because there is little demand for it.

    In order for the mills to pile the mulch high, they literally have
    have to drive the large front end loaders up onto the pile. Of
    course the weight of these large machines compacts the mulch
    in the pile, and this can become a huge problem for you or I if
    we happen to get some mulch that has been stacked too high,
    and compacted too tightly.

    When the trees are first debarked the mulch is fairly fresh, and
    needs to decompose before we dare use it around our plants.
    The decomposition process requires oxygen and air flow into the

    This article is continued below . . .


    Sue, I took some pictures of one of our plant
    sales. These photos show the front of our house, and
    all the plants we have for sale lined up in our driveway.
    Take a look:

    Growing and selling small plants is a blast!

    Starting this year, I plan to grow thousands of plants just
    to give away. Everybody on my mailing list will be eligible
    to win some of our plants. We select names from our list at
    random, and contact the winners by E-mail. So make sure
    you stay on this mailing list.


    article continued . . .

    When the mulch is compacted too tight, this air flow can
    not take place, and as the mulch continues to decompose it
    becomes extremely hot as the organic matter ferments.
    Sometimes the extreme heat combined with the inability to
    release the heat can cause the pile to burst into flame through
    spontaneous combustion.

    In other cases the mulch heats up, can not release the gas, and
    the mulch actually becomes toxic. When this occurs the mulch
    develops an over bearing odor that will take your breath away
    as you dig into the pile. When you spread this toxic mulch
    around your plants the gas it contains is released, and this gas
    can and will burn your plants. It has happened to me twice.
    Once at my own house, and once on a job I was doing for a

    This toxic mulch is very potent. We spilled a little mulch in
    the foliage of a Dwarf Alberta Spruce that we were mulching
    around, and just a few minutes later brushed the mulch out of
    the plant. The next day my customer noticed that one side of
    the plant was all brown. Not only did I have to replace the
    Dwarf Alberta Spruce, but the mulch also damaged at least
    10 other plants that I had to replace.

    I once saw where somebody ordered a truck load of mulch, had
    it dumped in their driveway, and as the much slid out of the
    dump truck onto the asphalt the toxic gas that was released
    settled on the lawn next to the driveway. The gas, not the
    mulch, turned the grass brown next to the mulch pile.

    This same person spread several yards of the mulch around
    their house before they realized the problem, and it ruined many
    of their plants.

    Now here's the hard part. Trying to explain to you how to
    identify toxic mulch. It has a very strong odor that will take
    your breath away. But then again almost all mulch has a
    powerful odor. This is very different than your typical mulch
    smell, but I can't explain it any better than that.

    The mulch looks perfectly normal, maybe a little darker in
    color than usual.

    If you suspect a problem with the mulch you have, take a couple
    of shovels full, and place it around an inexpensive plant. Maybe
    just a couple of flowers. When doing this test use mulch from
    inside the mulch pile and not from the edges. The mulch on the
    edge of the pile has more than likely released most of the toxic
    gas that if may have held.

    If after 24 hours the test plants are O.K., the mulch should be

    The purpose of this article is not to induce panic at the mulch
    yard, but toxic mulch can do serious damage. At my house it
    burned the leaves right off some of the plants in my landscape,
    and burned the grass next to the bed all the way around the
    house. It looked like somebody had taken a torch and burned
    the grass back about 2” all the way around the bed. If I hadn't
    seen it with my own eyes I wouldn't have believed it.

    That's it for now.

    Sue did you know that I also
    publish an internet marketing newsletter?
    It's pretty interesting if you have any interest
    in marketing any thing at all on the internet.
    You can subscribe here:

    Take care and have a great day!
    -Mike McGroarty

    Mike's Backyard Nursery
    P.O. Box 338
    Perry, Ohio 44081

    P.S. Do you need great gardening articles for your
    website or newsletter? Get them here:


    Click on the link below to remove yourself

    AOL Users
    <a href=""> Remove Me</a>
  2. Dchall_San_Anto

    Dchall_San_Anto Active Member

    Feb 17, 2004
    For all the smarts that author has, I wish he'd learn a lot more about organic gardening so he could do proper analysis on a problem like this. Pardon me but this article has every element of a hoax. While I don't doubt that the author got some bad mulch, I do doubt the reason stated for it being bad. There are a few reasons for mulch being bad but compaction is a new one on me.

    And if it smelled that bad, what was he doing putting it on his garden? Again, he needs a few lessons in organic gardening.

  3. Paquebot

    Paquebot Well-Known Member

    May 9, 2002
    South Central Wisconsin
    I agree totally with David. Toxicity by compaction? That's got to be the most far out excuse that I've ever heard of! Noxious gases would have no large voids to fill, in quantities sufficient enough to cause a problem. If they did, the mulch pile would simply explode like a bomb due to built up pressure! I've read a lot of Mike MrGroarty's stuff before. A lot of it is good advice and sometimes he's way out in left field with his scare tactics. Of course, using only HIS advice and subscribing to HIS newletter eliminates all problems!

  4. diane

    diane Well-Known Member

    May 4, 2002
    South Central Michigan
    :haha: Toxic gas?? Now perhaps there is something in that mulch that killed things, but I would not think it would be GAS. Gases, to the best of my knowledge, for the most part rise and as soon as exposed to air would be diffused. But then must be true.......I read it on the internet ;)
  5. gobug

    gobug Well-Known Member Supporter

    Dec 9, 2003
    Carbon dioxide is heavier than air. It is quicker and more lethal than carbon monoxide. It takes only a minute or two to euthanize a skunk, for example. Still, I think the posting is a bunch of hooey.