Tuesday, October 30, 2012

Wood chip soil pictures

The garden beds, which had wood chips dug into the soil, did the best this year.
So I decided to dig up soil in them and take a look at what was going on.

Most noticeably was that the plant roots all congregated where clumps of wood chips were buried.

Also very noticeable, there was lots of worms throughout all the soil, soil that had wood chips and soil that didn't.  In previous years I had never seen so many worms. I believe having the wood chip mulch encouraged more worms than the leaf and pine needle mulch that I used in previous years.  I had wondered if worms would feed on wood chips, it seems that they do.

Here are two clumps from the same bed.  On the left no wood chips had been mixed in. On the right lots of wood chips had been buried. Notice the almost total lack of roots on the left, yet these clump were only about 4" away from each other in the ground.

Another soil & wood chip aggregate from another wood chip bed. Notice the darker parts of the soil in this picture. These are worm castings. The soil had lots of worm casting deposits wherever wood chip clumps were, even over a foot deep.

Here I dug up soil from a regular hugel bed (horizontally placed logs).  In the spring I did dig in some pine needles & leaves, but they had totally disappeared.  The cucumber growing in this bed did ok, but not great. Cucumbers growing in the wood chip bed did great. Cucumbers growing in just a clay bed (no wood chips, no hugel logs) did very poorly (didn't produce any harvest).

There were lots of worms and worm holes in the this soil, but it was still thick clay and no where close to being as good as the soil in the wood chip bed.

It seemed the roots did best in soil that was about one-half wood chips!
Quite a surprise.

As another experiment, I had planted a couple seedlings above some wood-chip-only clumps in the soil that were about 3" deep and 5" diameter. The plant roots did not like growing into only wood chips and these plants didn't do as well.

Seeing how well roots did in "wood chip soil", has given me confidence to really go all out when digging in chips. I had wondered what would be too much. But it seems even 1/2 chips, 1/2 dirt is great for the plants.  If I had seen this before I prepared my 4 new hugel beds, I would have dug in even more wood chips. For the 2 existing wood chip beds, I'm digging in a lot more chips now, before planting fava beans.


  1. An excellent post and one that we will be taking note of when we start chipping the garden debris that we are leaving on the bare soil (where it fell) over summer. I have just started dabbling in Biochar and discovered hugelkultur garden beds recently as well and am leaving a huge rotten fallen tree over in the corner of the block to see how the soil reacts to this bounty. A great post on the chips by the way. I would imagine that the result is because of the increased surface area under the soil that allows moisture and air to infiltrate that has given you these amazing results. We, too, have clay subsoil and are in the process of building it up before it sets rock hard over summer. Cheers for this informative post :)

  2. Really cool. Perhaps the extra moisture capacity of the wood made the worms happy.

  3. Actually the soil was drier in the wood chip clumps. Most likely because the roots where drinking the water. The only clay clumps were wet, no roots to wick away the water in them.

    The chips seem to have started the whole "Soil Food Web" (good book that I just read) going. Lots of mycelia were breaking down the chips, leading to,....

  4. Very interesting... I'll bet you're right.

    I've also heard that fungi can carry water and nutrients long distances and into the root systems of nearby plants.

    (BTW - I added a link to your blog on my sidebar at Floridasurvivalgardening.com.)

  5. Your results are fascinating, especially given the prevailing wisdom that warns against digging wood chips into the soil due to nitrogen immobilization. My understanding of how hugelkultur circumvents this particular problem is due to the smaller surface area of logs vs chips, but it would appear that, if your plants prospered, nitrogen immobilization wasn't a problem for you. Did you fertilizer these beds any differently than you would have otherwise?

  6. The plants in this bed did have yellow leaves after transplanting for awhile until I dumped about 10 cups of HLF (human liquid fertlizer ... urine) in the bed.
    I fertlized again with 10 cups about a month to 6 weeks later. Then it was fine, plant leaves stayed green.

    In my clay only beds(no wood chips, no logs) I actually added more fertilizer over the summer and the the plants were still yellowish. I believe that the fertilizer just washed away with nothing to hold/bind it.

    So the wood chip bed did need a couple big doses of nitrogen fertilizer, but overall didn't need as much as clay only soil.

    In another board, someone mentioned they just use urea and wood chips.

  7. I have done this before in Elkhart, IN with spectacular results. I once took a screen and sifted my soil taking all the debris out. That section of the garden did not grow anything at all. So then I decided that my soil needed debris. I tilled wood chips in the next year and it was exactly the opposite. I had great results. So this is how I have been gardening since the mid 90's.

  8. Good comment wbliss. Since starting this I've wondered why anyone would want to sift compost, better to just put all debris/chunks in the ground.

    1. Absolutely, I just talked to a guy at the Niles Community Gardens and I was trying to tell him about this and he told me how he mulches his wood chips and will not till it into the garden until they fit through his sifter. I sent him this link. Hopefully he eventually understands it. BTW it was the soil in the garden that I sifted really fine. It promptly packed down tight and no plant could survive in the soil. So then I got the idea of putting wood chips in it to provide moisture holding capacity and air. Another good link on the subject that explains some science behind it:

  9. BTW, after the first year of tilling the wood chips into the soil I discovered I no longer needed to till. The worms just churn that soil during the winter just as if I used my tiller. When you step on it your foot sinks in. I just add wood chips on top when needed to block the weeds and the worms do the rest. I move the wood chips aside to insert plants or seed.

  10. This post has really inspired me. I absolutely love your experiment and the RESULT! I linked to this post from my blog if that's ok. This year we mulched with woodchips in every single garden bed here. I took the plunge and mixed it into my vegetable beds with darn good results. I also did a side by side pot experiment. 1 with bagged soil (did awesome) 1 with our potting soil mix (really bad, killed the plants!) and 1 with our potting soil mix 50/50 with woodchips... this did almost as well as the bagged soil. My conclusion in theory is that woodchips help with drainage while retaining moisture.

    Thanks again for this post, im really gung ho for woodchips and super excited with the results. looking forward to better and better plants as I learn more.

    1. I forgot to mention another great benefit. As a mulch it really keeps the weeds down. What weeds grow are easier to pull. And it helps cut down on watering

  11. I'm going for it I have heard about the chips taking away from the soil. I have also heard if u cross a dog with a cat your get a dat who dat go Saints lol. I have cut down a few trees and bought a chipper so I'm got lots of chips I also am going to try out a few worm beds

  12. Great information, thanks. Does anyone know where to get wood chips for gardening in the Elkhart area? I live in Bristol.

  13. Anonymous: When trees are being pruned in your area is the best time to get fresh wood chips. Call your Arborist ask to be put on his list. Most will happily donate to your "pile" Be prepared though... It might be surprising how much he donates. lol

    To the Blogger: When you mixed your chips in were they aged or were they fresh from the chipper?

  14. This is a really good read for me, Must admit that you are one of the best bloggers I ever saw. Thanks for posting this informative article.
    Mulch Garden