Wood Chips for Mulch – Answering a Reader’s Question

Steve, a reader in Lubersac, France, emailed me to ask if I envisioned any problems using willow tree residue (that has been shredded) as mulch.

Willow for firewood is Steve’s main source of heating and hot water. He’s just starting to harvest his first crop of willow and is left with all the thin straggly bits, except for the ones chosen to start new trees. He explained that the residue is a considerable amount.

The local town hall there has recently embraced a ban on bonfires to cut down on pollution. (This might be admirable except for the fact that a farmer can still burn all his rubbish including plastic seed and fertilizer sacks!)

Steve would have burned his residue had the ban not been put into effect.

Sad that lots of folks burn or trash great organic material, including leaves, that could be recycled to make their gardens even better and more productive. They just don’t realize how valuable these materials are to their garden!

Wood Chips

I would define wood chips as any wood that has been shredded in some manner.

Primary Concern About Using Wood Chips for Mulch

The primary concern about using wood chips for mulch is that the newly shredded wood may cause soil life to use available nitrogen in the soil to break down the wood chips, rather than making it available for any crops that are growing.

And that’s the thing you want to avoid. By testing your plan in a small area rather than on a large scale, you should be able to prevent any major problems.

The Other Concern that Comes to Mind

The only other concern I can think of is if the wood chips are from any species of the walnut family (for example: black walnut, hickories, pecan, butternut) which produces juglone in the soil where it grows and within about a 50 foot radius of the dripline. This substance can kill plants like tomatoes, peppers, potatoes and eggplant. Not all plants are sensitive and thus not damaged. Corn, beans, beets, carrots and onions are tolerant of the juglone, as are most trees, shrubs, annuals, and perennials.

Fortunately, even leaves and shredded wood of these trees can be used if composted or aged long enough to allow enough time for air, water and bacteria to break down the juglone and render it harmless. (For the leaves I’d age or compost at least a month and for their wood chips I’d recommend at least 6 months or more to be safe.)

Be Safe – Go Slowly – Test

Over the years wood chips have always been one of my favorite mulches and I have used them with great success.  In spite of that, since there are always so many variables from one garden to the next, I would recommend moving slowly and “test” before you do anything on a large scale.

As Mulch on Top of the Soil – Your Safest Bet

If you use wood chips on top of the soil, it is highly unlikely that you would experience any adverse effects.  Test a spot anyway just to be safe.

Incorporating into the Soil where Crops are Growing – May Cause Problems

If you turn the wood chips into the soil, you just may experience problems if you have crops growing in the same soil while the wood chips are decaying.  The soil life will work on breaking down the chips and they use nitrogen to do it.  Therefore, the need for nitrogen by any crops growing in that soil will be neglected until the chips are broken down.

My Experience With Wood Chips

Years ago, before I knew anything about nitrogen and how soil life worked, I dug many a wheelbarrow of wood chips into garden beds.  I had no adverse effects, in spite of the fact that the people who sold us the chips warned us about it.

Not sure why they never had an effect on the other plants.  Maybe they were aged enough.

Since we could get a dump-truck load of chips for only $20, we always kept at least one big pile of chips.

Here are my favorite uses:

  • After digging out about 6 inches of rich soil from my garden paths and tossing it up onto my garden beds, we’d fill up the paths with wood chips, making it level with the beds.  After a year or two the chips turned to black soil.  Then we’d dig  out the paths again and toss it onto the beds and refill the paths with new chips.
  • Edging all the gardens and borders with a heavy (almost a foot deep) layer of chips.  This kept the grass from edging into the beds and when it started into the mulch it was easy to pull out.
  • Mulched all my flowers borders with it.
  • Mulched a lot of my garden beds with it.
  • Incorporated it into any new beds being created.

No Chipper/Shredder

I don’t have a chipper/shredder but I still try to keep as much debris from pruning as I can.

For example: when I trim my back-side border hedges each year, I cut most of the limbs into 4 to 6 inch pieces and leave them where they fall to serve as a mulch for those borders.  It’s not shredded as I would prefer, but it works and the pieces eventually decay and recycle to feed any plants in that border.

Final Thoughts

Any wood you can shred and use – do it!

Over the years Steve’s debris from the willow harvest will save him lots of money that he may otherwise spend obtaining mulch from other places.

There is always a time and place that a gardener may prefer straw or some other mulch rather than wood chips on certain beds.  But for the most part, the wood chips  will get the job done without his spending money on some other form of mulch.


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  • Theresa

    I know they tell you to be careful putting wood chips next to the house as it may draw termites. I don’t know if that is a concern at all for a garden.

  • i use wood chips in my horse’s stalls and I would like to use the droppings and muck for my gardens. 2 questions: how long would you reccomend that the compost pile from the stalls break down before use and would it be organic if the origin of the chips is unknown.

  • Thanks Theresa,
    I knew I could count on your extensive knowledge, so freely given, to point us in the right direction.
    Ronda, what a great link too, so many thanks to you too.

    Now to get well and truly Mulched UP!


  • I’ve noticed that the willow limbs in my yard tend to sprout roots easily, especially when damp and/or partially buried outdoors. Might this be a concern when using willow as a mulch?

    I love your blog and emails, and am learning so much about food gardening from your information. Thank you!

  • Hi Paula,
    Yes you are right, willow does root easily.
    Makes expanding a willow plantation a doddle,thankfully!
    I’m not so sure the shredded state leaves any viable bits for this.
    Not that I am any kind of expert though, so will keep an eye out and report any sprouting, here.


  • Hi Beppy! Glad you enjoyed the article and appreciate your saying so.
    We haven’t frozen, but it has indeed been quite a winter in more ways than one!
    The severe challenge we’ve had will effect my gardening this year. But I’m looking forward to learning more this year than ever because of having to deal with adverse circumstance which will make this year a real learning experience!

    Wood chips next to the house will definitely attract termites. You’d never want them right up next to your foundation.

    Regarding termites in the garden etc. — termites are always in the ground and they surface when something like decaying wood or wood chips attracts them. So they can definitely be in the garden. I’ve had them in mine several times but they’re fine because – unlike when they attack a home — they’re just doing the job nature meant for them to do.

    I enjoyed the article that Rhonda gave a link to, but have had different experiences with termites than they or their sources have had. In the Q&A part the question was “Will wood mulches attract termites — and other pests?” Their answer was “No.—” My answer is “Yes”

    I’v seen termites come up into my piles of wood chips. (The termites were not there when the pile was delivered.)

    I’ve also seen termites come to my garden paths that have been filled with wood chips.

    It’s not the vast percentage of time that these things happen but it happens often enough that I know the wood chips are a draw.

    I don’t think there is any “set in stone” time to compost, but I would lean towards an average of at least 6 months. In any event it needs to be well rotted (or composted).

    If the chips of unknown origin (or the manure) contain chemicals that are broken down in the composting process — you’ll be fine in using them on your organic garden. If they contain chemicals that cannot be broken down or that take years to break down, your garden may suffer harm from the residual herbicides. See my post for more information.

    Ronda, thanks for letting me know that you’ve benefited greatly from my advice!

    Thanks too for posting the link to the article on wood chips as mulch. It compliments the information in my post and I think readers will benefit from it.

    The article specifically addresses arborist wood chips which contain bark, wood, and often leaves. The wood chips that I use to have access to contained only the wood. As the article pointed out, arborist wood chips are better from the stand point of that important principle: diversity. More diversity in the composition of the mulch means more diversity in “microbes, insects and other organisms.” A good thing for your garden.

    Also, I don’t think it was mentioned in the article, but arborist wood chips are more like composting in place since it has both greens (foliage) and browns (wood and bark) necessary to compost. It feeds the landscape it mulches even more than wood chips composed only of wood.

    The closest I come to arborist wood chips on my property is my small-cut prunnings of various bushes and hedges in my back borders. It’s not shredded of course. Just cut up by me as I prune. But it serves the same purpose only at a probably slower speed.

    Hey Steve. Thanks for joining in!

    Paula, many shrubs and trees sprout easily from cuttings. I’ve even had a couple of buddleia root over the winter from pruning debris left on the border the previous fall.

    I would not think this to be a big problem unless one had acre upon acre that they were unable to tend on a regular basis. If something does come up that’s not wanted, it can easily be pulled out when discovered.

    Steve will let us know more as time goes on. (Thanks Steve.)

    Glad you are learning from TMG Paula. Thanks for letting me know. Keeps me writing!


  • I’ve lost count of the number of barrow loads of wood chips I’ve put into the paths of my garden. It’s amazing where it all goes. I have piled up to 24 inches onto my paths in spring and by the next year, the paths are down to almost their original level. The soil in the path does make a good topper for any bed that needs it, and the worms are busy under the chips. Here, we don’t have to pay for it – YET.

  • We used wood chips for mulch in our backyard border. Seemed to all go well, then we had some moderate rains and the mushrooms popper
    . Then I noticed around some Hosta’s a white thick growth around the stems. Today I watered them and a large mass of powder residue came up in the air all against our fence. There were a couple of area’s close together of this. I kept rinsing until it was gone. What could this be ?

  • Lot of fungus (not harmful to your garden) develops at various times on wood chips. Sometimes it’s white; sometimes yellow; sometimes pink.
    The first time I saw some of it many years ago (maybe 35 years ago) I thought some dog had gotten sick there. Then I wondered what all of us wonder when seeing it for the first time — Is this going to harm my stuff?

    Usually when it’s just on the ground or near plants, I just cover it with a shovel full of soil.
    For the stuff in your hostas you probably took the best approach by washing it off until it disappeared.

    Fortunately this doesn’t occur all the time and not everywhere; just some of the time and in spots around.
    Hope this helps Sharon.

  • I started a new garden here and the soil is very different from what I am used to. Clay, sand, super ascetic and low in organics. I added several cubic yards of mushroom compost, composted manure. It is only 32×36 so not a huge garden. I intend to not succession plant this year so I can super amend the soil for next year. I know that tilling is not recommended but it would take forever to get the amendments into the soil if I don’t. I also have wood chip paths and back home used them always to keep path weed free and indeed, year after year I would have to add more. lol. Guess that was a good thing.

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