Adventures in Hugelkultur in Australia

http://www.youtube.com/embed/xQUiKqU19y4

A while back, the Permaculture Research Institute of Australia presented an article on hugelkultur raised beds (see also here and here). I found the idea of planting out raised beds made of tree saplings covered in a bit of soil and woody mulch to be intriguing.

I’d never heard of hugelkultur before, but living surrounded by eucalyptus forest started me thinking about the possibilities. I’m not sure that hugelkultur techniques are practiced in Australia and perhaps the reason for this is that eucalyptus trees can take many decades to break down into soil. This is probably a bit slow compared to the tree species used in hugelkultur beds in Europe.

A possible reason that the trees take so long to break down into soil is because of the frequent and intense bush fires which char the trees and leaves a coating of carbon on them which makes them difficult to breakdown and impervious to water. In addition the bush fires interrupt the life in the soil by burning the soil. There could be other possibilities as well. If you have any ideas, let me know.

Then, in a surprising discovery a few weeks back, possibility turned into opportunity…. When I was moving cut and seasoned firewood logs from a stacked pile to burn for heating fuel, I discovered a fungus which had taken hold on the firewood logs and was converting them into soil within years (as distinct from decades). It was a eureka moment!

So, I decided at that moment to establish two experimental Hugelkultur raised beds and to inoculate the beds with my newly discovered fungus. To further pretend to be a scientist, one of the beds has larger diameter saplings, whilst the other has several smaller diameter saplings and I’m going to see which proves to be the most fertile.

Into these two hugelkultur beds I’ve planted all of my raspberry and blackberry canes.

I have high hopes for this experiment and as the experiment continues and evolves, I’ll keep readers posted.

If anyone else is experimenting or practicing with hugelkultur, I’d love to see you sharing your experiences via comments below, or, better yet, via your own posting on this site.

Related

Popular

23 thoughts on “Adventures in Hugelkultur in Australia

  1. I am fascinated by Hugelkultur. I have a big pile of rotten firewood which I know has some black walnut included. It is all rotten enough that I really cannot tell which species are which. I know that planting under a black walnut is pretty much impossible, so I wonder if it would be a problem in a Hugelkulture bed.

    1. https://www.permaculture.co.uk/articles/many-benefits-hugelkultur

      from above website :)
      – Woods that work best:
      Alders, apple, aspen, birch, cottonwood, maple, oak, poplar, willow (make sure it is dead or it will sprout).

      Trees types that work okay:
      Black cherry (use only rotted), camphor wood (well aged), cedar/juniper/yew (anti-microbial/anti-fungal, so use only at very bottom or unless already well aged. Cedar should be broken down before new plant roots reach it), eucalyptus (slightly anti-microbial), osage orange (exceptionally resistant to decay), Pacific yew (exceptionally resistant to decay), pine/fir/spruce (tannins and sap), red mulberry (exceptionally resistant to decay).

      Tree types to avoid:
      Black locust (will not decompose), black walnut (juglone toxin), old growth redwood (heartwood will not decompose and redwood compost can prevent seed germination).

  2. I enjoy reading learning and sharing your articles. Maybe you could add the option to share on twitter. Just a thought to help spread and share your knowledge.

  3. Hi Kate – please hover your mouse over the ‘share the knowledge’ icons, and you’ll see Twitter show up on the second row (which drops down, when hovering).

  4. Barbara, I don’t think you need to worry that there is some walnut amongst your rotting wood. Most of the incompatibility of walnuts is in the root zone while the walnut is growing. There may be some tannins in the walnut but if there is already fungal activity breaking everything down, then the processes you need in your Hugelkultur bed are already underway.
    Chris, good one, great idea to inoculate the pile with some existing fungi, it may have found its way there eventually but this will certainly speed up the process. I will be keeping my eyes open now for different fungi I have on my site that are breaking down eucalyptus and wattle.

  5. I’ve had huge success with hugelkultur. Three months ago I created 8 raised beds using a combination of hugelkultur and lasagne gardening. We have had an abnormally dry summer season here in Nova Scotia, Canada but my gardens seem to be thriving with the rotting logs holding water and various layers of mulch. I was unsure of the logs which had fungus growing on them, but believe it only adds to the whole ecosystem within the raised beds. I did find a “dog vomit slime mold” (yes it’s the name of a real amoeba) in my gardens that turned out to be a truly beneficial mold I believe this came from some of the rotting logs I had used. It’s all an experiment and i’m so happy that I decided to go with it.

  6. I read the article on HugelKulture in PRI and was inspired to experiment. We now have 3 HK beds, with potatoes, zucchinis and tomatoes growing in the first, with herbs around the base. Good to read more hints on what to incorporate into the eucalyptus branches. Patience a key ingredient. There are some wonderful blogs on this fascinating process.

  7. Hi – great posting I’ll be watching like an eagle for updates. I’ve been intending to try out a hugelkulture bed too since Ive got some old logs. I also have an old treestump in the backyard which I would hugelkulture over too except that during a recent termite inspection the pest controller pointed out that the stump has arsenic and lead in it from some really long time ago before I lived here when pest control mustve sprayed it… I dont know I suppose it wouldnt matter for ornamental use…

  8. I think most of the resistance of eucalypt wood to breaking down has to do with the density of the timber in some species, particularly the ironbarks. Most of the breakdown resistant compounds are found in the leaves. But for sure, where eucalypts are growning in Australia, there will also be fungi adapted to breaking down the dead meaterial (not to mention termites and other beasties). The lack of such co-evolved breakdown organisms is one reason for the bad name eucalypts have in countries where they are not endemic.

    However, in Australia I have seen people in the countryside use log heaps pushed up during land clearing as a “primitive” form of hugelkulture – throwing all their garden waste, saplings, and other organic material onto the heap – including things that sprouted or struck as the breakdown process takes hold. Our neighbours, for example, have such a log pile and it produces the most amazing volume of fruit, including passionfruit and dragonfruit, as well as being a visual delight with all the flowering species that are thriving there.

    For sure I’m going to be trying this with the thinnings from our firebreaks combined with fowl manure and the products from our chip mulcher.

  9. Hi Barbara,

    You’ve already got your hugelkultur bed going!

    Growing underneath a walnut (I’ve got 2 trees here) tree is purely for grass / herbage because the tree roots secrete juglone, which means the tree doesn’t play well with others. However, I reckon the timber would be fine to put into a hugelkultur bed. By the way it is a very valuable furniture timber, so other species may be better suited to a hugelkultur bed. As this is all experimentation, you may want to consider keeping us updated?

    Hi Kate,

    Thanks. There’s more to come in the future!

    Hi Craig,

    Thanks, I wasn’t aware of that option.

    Hi Carolyn,

    Thanks. Yeah, I’d never found that fungi anywhere around here before, but given the logs are local it must be around, so it’ll be interesting to see how it goes. Keep your eyes on the lookout at Mudlark and you never know what you might find. Hope the recent rains have been good out your way and that the swales are full.

    Chris

  10. Hi Lala,

    That’s a nasty sounding mould! hehe! I hadn’t realised that drought extended as far north as you. We get them here, so you have my sympathy. Well done, mulch and organic matter is the trick to getting through drought conditions here too. Glad to hear your experiments are going well. Perhaps you may want to write an update or send some photos?

    Hi Carolyn,

    Yeah, it was a good article and I’m glad to hear that you were also inspired to give hugelkultur a go. Well done. Yup, eucalyptus timber can be very slow to break down into soil. Keep an eye out for fungi and remember to innoculate your soil.

    Hi Katrina,

    What a good idea, I’d never have thought about hugelkulture over a stump. Did the pest controller mention the quantity of arsenic and lead in the stump? Arsenic is present in all soils in minor trace amounts, so that may not be too big of a problem. Lead is not good though as it accumulates in the body. You never really know the history of a site. Here, I’ve had to dispose of a dumped burnt out vehicle and the remains of an old burnt out timber getters shed. No place is perfect, you kind of make the most of what you have and urban sites can be far worse.

    Hi Gordon,

    Yeah, you are spot on. You can see a distinct line here in the herbage between the food forest and the eucalypt leaves drip line. I’m not sure what substance those leaves emit, but given that eucalypt oils can be used as an anti microbial / anti fungal and all purpose heavy duty cleaner you don’t have to wonder too much. Australian eucalypts are grown widely overseas and I wonder about the increased fire risk from this species too?

    Ironbarks are even more dense than the timbers here. They are about 750kg/m3 density, compared to 650kg/m3 for the eucalyptus obliqua (messmate) here. I think they use Ironbark for structural and furniture timber too and the timber itself looks awesome.

    You and your neighbours are on the money too. The chook manure would be a great addition to provide nitrogen and increased bacterial activity. I’ll add chook manure over the next month or so.

    A chipper would be very handy!

    I forgot to mention in the article too, that in addition to the composted woody mulch, I also mixed in a quantity (a bucket) of wood ash. More was applied to the raspberry bed and less to the blackberry bed.

    Regards

    Chris

  11. Wow, we have been using this method for our garden beds for years… never knew anyone else had ever done it or that it was “invented” by someone and a special name given to it? Just seemed a sensible way to use up old logs and tree branch cuttings as a foundation for a garden bed which would provide stability and height for the bed, store water and break down to provide nutrients over time.

    We also have a method where we plant inside a hay bale. Place your bale where you want, dig some holes into it and plant your seeds or seedlings… the bale provides stability and protection and breaks down over time to provide extra nutrients. This is particularly good for root vegetables (carrots, potatoes etc) and is also a good way to discourage chooks from digging up the garden. If you use barley straw, you get the added bonus of barley grass growing up through it wherever there are still seeds in the straw :)

  12. Hi Jules,

    The hay bale idea is great, it’s good to hear that it works well with vegetables.

    Yeah, I saw some bales for sale today in Trentham that had sprouted with all of the rain! Great to hear about your experiments.

  13. This looks a very promising way of passively irrigating, and also using organic matter that most people would simply burn off. There are property’s near me that have huge amounts of wood and branches, from 90 year old windbreaks of pine, piled up in massive bonfires. I might try asking them if I could pinch some of the wood.

    Do you think using woodchips would be as effective? I know that would be easier for me to find, as a lot of council tips let you take it for free. I guess it might not hold as much water and would break down faster…

    Anyway, good luck!

  14. Wow. I’m wondering if a fallen saguaro cactus in Phoenix, Arizona could be used for this. They are almost 100% water. Has anyone tried it?

  15. Eucalyptus oil contains cineole, the same compound that you find in tea tree oil. It is germicidal and I wonder if that is one of the reasons that it takes so long for your trees to break down? The nature of the tree is anti-microbial. We have difficulty with this in Canada with Cedars.

    It would be interesting if the fungus you’ve found is immune to cineole!

    L.

  16. What a great question. I don’t actually understand the chemistry behind eucalyptus oil, however it too is used as an anti-bacterial agent so you observation is most like correct. There is actually quite an easily observable line between the drip lines of eucalyptus trees and the herbage in the food forest.

    As a bit of an update, I have recently removed the hugelkultur beds, not because they are a bad idea, but because the recently finished summer into early autumn, the climate here was so extreme (more than any in recorded history ie. since 1853) that the beds themselves dried out and the plants died. The hugelkultur beds were established just at the beginning of a long and unprecedented failure of the spring and summer rains which lasted for about 5 months, so they really didn’t have much of a chance.

    The several cubic metres of organic matter was redistributed into the food forest where it kept the roots of the fruit trees cool during the extended and successive heat waves.

    However, perhaps on consideration, it was actually a matter of timing and patience because some of the firewood piles are actually breaking down into rich black humus and I’ll include a look at this process in the next update video (early Winter / June 2013)

    As an interesting side note, the established fruit trees in the food forest continued on mainly unaffected by the heat. They showed very little signs of heat stress as the well established top soil and herbage cover held good quantities of ground water. I’ve also since planted large quantities of comfrey throughout the food forest.

  17. Im looking at putting raised beds down the side of our property and at the same time the need to cut down a large old Swamp Banksia which is dying and will need to go due to the fee risk. Do you know anything about Banksia composting in these hugelkultur beds?

  18. Thanks for the article, Chris. I’m in the UK. There are some fat eucalyptus logs that are rotting well after around 5 years, even one sitting on a step with no contact with the earth is riddled with myceleum and disintergrating.

  19. What about the leaves on the ground, under the eucalyptus? Will they eventually decompose and leave way for other growth? There are large areas of eucalyptus around here — 380 acres — where the ground beneath is devoid of growth. Might we be able to inoculate this ground cover and convert it into productivity? Allelopathy might then, be reversed …. ? Anyone ?

Leave a Reply

Your email address will not be published. Required fields are marked *