Where’s the Bark Dust?


If you didn’t realize how much your garden depended upon the housing boom and busy sawmills, check out the latest issue of Digger, the magazine of the Oregon Association of Nurseries.  According to author Curt Kipp:

  • The housing boom meant an increased demand for lumber.
  • To get lumber, you cut down trees.
  • A lot of those trees are in the Pacific Northwest (a very environmentally-aware reporter visited me recently and was surprised to see redwood logs on their side at the mills.  "I thought we stopped cutting down redwoods," she said, shocked.  Nope!  That’s where boards and paper come from. Got a plan to wean us off those products?  Hint:  it’s called hemp.  But that’s a rant for another day.)
  • One of the by-products of a busy sawmill is lots of bark dust.
  • An industry formed around re-using bark dust in potting soil mixes, growing medium, and mulch.  Many container plants are grown in a ‘soilless’ medium that is 50-100 percent bark dust.
  • It just so happens that bark dust is perfect for this.  Holds water but promotes aeration. 
  • Fewer houses = slower sawmills = less dust.  Also, sawmills are better than you might expect at reusing and recycling. As fuel costs increase, they tend to reuse their waste products as fuel to both power the plant and feed energy back into the power grid.

So the whole soil mix industry is having to find alternatives to bark dust.  Peat moss is scarce and non-renewable, pumice is expensive, and composted yard waste is not available in large, consistent quantities.  So what’s left?

Garbage.  Not green waste, but actual unsorted household garbage, minus the glass and metal.  A company called WastAway is doing it, and the result is a product called Fluff that can be used as a grow medium or pressed into boards. While there is no specific description of what Fluff contains, one assumes that "unsorted household garbage" minus glass and metal means plastic, cloth, paper, food scraps, diapers, kitty litter–whatever you throw away.  Fluff is heated to kill microbes, and, according to the website, tests show that the process ‘neutralizes the dangers’ of chemicals in the waste stream.

The generic term for a product like Fluff is ‘composted municipal waste.’  Now, regulations governing product labels on bagged compost and potting soil products vary by state, and there’s lots of room for creative lingo.  But would you buy a bag of brown stuff if you knew it contained Fluff?  Would you eat food grown in Fluff–and how would you know whether that tomato seedling at the garden center was grown in the stuff before you took it home?  Do the benefits of re-using our garbage and getting away from dependence on forest products outweigh any questions over the application of shredded plastic, household chemicals, etc in our gardens?  Are we simply spreading our landfills around? Should Fluff be reserved for boards and other ‘hard’ products instead?

Other interesting options for alternatives to forest products in soil mixes, according to the article:  rice hulls, corn husks, and waste products created by the manufacture of coco fiber.


  1. fluff sounds so harmless until you hear what its a name for! I think coir (some sort of coconut derivative) is the big peat/dirt replacement development in the UK.

    The best such product I’ve heard of was a garden somewhere in the islands that uses nutmeg husks (or shells or whatever the industry term is) as mulch giving the whole gardens a neat bakery smell as you wander round it.

  2. What about coffee grounds? I have been using the ones starbucks gives away in my compost and it works great. It is kind of finely ground though so it helps to mix it with something else. If we all just drank more coffee….

  3. What about coffee grounds? I have been using the ones starbucks gives away in my compost and it works great. It is kind of finely ground though so it helps to mix it with something else. If we all just drank more coffee….

  4. No Fluff in my garden, thank you very much! I wouldn’t touch the stuff.

    Maybe we could combine the nutmeg husks, coffee grounds, and coir. We’d have eggnog coconut latte scented potting mix!

  5. I think that coffee grounds would be to acidic for a potting mix. But we need to come up with some alternative, that Fluff sounds nasty!

  6. Shira – that is the weird thing about coffee grounds. Their PH is around 6.5 which is basically neutral. I guess we leach the acidic part out when we make coffee.


  7. We’d have to drink a *lot* more coffee for there to be enough spent grounds to be a viable alternative for the nursery industry. They go through heaps (and heaps and heaps) of bark dust. Not sure I want to be that big of a coffee junkie. My waistline couldn’t handle it either (straight coffee? No way, how boring, it must at least have cream).

    I haven’t made up my mind about Fluff yet. Love the idea about recycling garbage that would normally go to the landfill (it’s all going into the ground one way or the other, I guess). I hope we see more studies done on the product.

  8. Studies yes indeed. This sounds similar to much of the treated sewage sludge fertilizers that are on the market currently Huaconite, Milorganite,etc… While on the outset it sounds good, levels of various toxins/heavy metals have shown up in the products. Now a used Pampers (we call them cheeseburgers when we see them tossed out in the parking lots and landscape)probably retains moisture quite well.
    We do cloth, so we won’t contribute.
    Garbage farming is the wave of the future as now we must grow crops for both food and fuel. “Don’t have a cow man!”
    Some of the best Basil I have grown was fed every morning with coffee grounds!

    Rant on!

  9. I used to live near these Wastaway guys and the smell of their plant is awful. There is no way I’d put this on my garden. Imagine if you will taking your garbage and pressure cooking it until it is almost burned. They don’t even get the plastics nor some of the metals out of the stuff.

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