Animal ProcessingFood ForestsTrees

Making Bone Sauce

by Paul Kean, Tiger Hill Permaculture

Tiger Hill Farm is situated in the Southern Midlands in Tasmania and is set amongst 10,000 acres of mixed private forestry and crown land. The farm is 70 acres in size and is home to Tiger Hill Permaculture, a registered primary production business and private farm forestry project. The long term vision is to align with the PRI Master Plan by becoming an educational community demonstrating sustainable agriculture and self-sufficiency via Permaculture design.

Having been on the property now for 4 years and taking into consideration the effects of everything I do on the land, I have observed closely the local environment. As I am funding the project solely from a salary income, I have weighed up numerous options for a multitude of small to large projects on the site in the hope to create cost effective solutions to my design strategies.

When I first took over the farm, there were several apple trees, peach trees and a plum tree growing. These trees were doing ok as they had been well tended by the previous owner and for the first couple of seasons under my tenure they bore fruit. As I work away from the site a lot and at times have to spend extended periods working overseas, the trees became a little neglected and possums made regular visits to eat the leaves and fruit as well as break branches — and so they were soon no longer producing at all. The property is mainly pasture along with some forest stands and a host of wildlife — wallaby, wombat and native rats are in abundance, as are the possums. The wallabies don’t pose an issue and while the native rats do eat the fruit they are not a real cause of concern.

The feedback loop I got from this was that the previous owner having had a dog on the farm full time may have kept the possums at bay.

I continued to observe the trees and to go through the process of what if I did this or that. With a limited budget, I considered the following:

  1. Get a dog. This is the easiest solution. The only problem is I still work off-site regularly to fund the project and who will look after the dog?
  2. Fully fence the entire house envelope with poles and netting. This would be great and the system would also protect free ranging chicken in the future from wedge tail eagles. This, however, is a very costly strategy as well as requiring a huge amount of labour to install.
  3. Fence the entire house envelope with floppy fencing or similar. This is practical, as I did need to replace the existing fencing around the perimeter in due course, but also a costly exercise.
  4. Install individual floppy fences around each tree. This is a good one but requires a reasonable amount of maintenance and infrastructure to make it work well as the trees are planted randomly within the housing envelope.
  5. Install floppy fences and back it up with an electric fence. Again, some infrastructure is required and as I do the majority of the work on the farm myself, I would be continually worn out maintaining it.

Heavy duty galvanized chicken wire runs at about $180 for 100m x 1.2m x .4mm. High tensile ring lock is a bit more expensive and I would need to use both for the perimeter of the housing envelope to deal with wallabies as well. My house envelope perimeter is approx. 400m and at some time I will need to do this but only as funding is available.

Recently I watched a YouTube video where Sepp Holzer, of the Krameterhof in Austria, was making a concoction from bones cooked in a cast iron pot that repelled wildlife from eating his trees for up to 10 years. I saw this as pure gold and possibly the answer to my problem, as shooting possums is illegal in Tasmania and I want a human solution that fits with my ethics. I watched the 8-minute clip and it seemed so simple.

I weighed up the pros and cons of recreating this video message to make the sauce on site. It seemed straightforward. I am not fully sure of the science of the whole process yet but if Sepp says it good then that’s good enough for me. I thought this was by far the cheapest alternative to my many other thought processes. If I could make the same sauce, it would also reduce the amount of labour I need to maintain the trees considerably. This would then allow the trees to recover from the Possum onslaught and allow some further time to save toward a more secure solution. As the house envelope is my Zone 1 and 2, and the area is intended for more intensive garden systems, the fence is definitely needed in the near future.

I set out to make the sauce as well as filming the process as an educational tool with the assistance of Anders, a volunteer from Denmark enrolled in the Workaway program (similar to WWOOF). Anders was very instrumental in editing the final product to put onto YouTube and as well as being great sounding board to help problem-solve any issues that we could address. I have a steady stream of volunteers come to help and they are all so keen to learn new things and help work towards my vision of this project.

The making of the video was my first attempt at filming in front of the camera for video documenting on the farm so we created a plan by making a story board and creating the steps of what we would do and say. I’ve seen some pretty ordinary B grade movies in my time, so I figured it can’t be that hard. This was a great learning experience for both Anders and myself as it was the first for us both to do the filming and editing of a complete shoot. We have both remained grounded and the minor celebrity status has not changed us.

After making the sauce, it was applied to some trees. Some say to apply the sauce during the dormant stage of growth in Autumn. We applied it at the start of Spring. This was purely to get it on so any new growth may be protected. We will see in time if it has been positive or negative.

What you need for bone sauce:

  • 2 x even sized pots (any capacity, cast iron preferably)
  • approx. 1/8th litre of water
  • bones (enough to fill one pot)
  • small gauge wire mesh (cut to a bit larger size as diameter of pots)
  • clay (to seal between the two pots)
  • fire starter (matches or lighter)
  • a quantity of firewood for continual burning for up to 2 hours
  • loose dirt
  • shovel
  • broom
  • 1- 2 jars, depending on quantity of resulting bone sauce
  • paint brush

Method

  1. Choose an area where wind will not present a problem when lighting a fire.
  2. Select pots — we used 2 x 10 litre cast iron camp ovens. Remove handles and lids.
  3. Dig a hole to suit the outside diameter of the pot. A snug fit is best. Dig the hole so the pot sits on the base of the hole with at least 20mm of the pot protruding from ground level. Level the pot as well as possible.
  4. Pour in approx. 1/8th litre of water.
  5. Add bones into the second pot, and pack down firmly. Take the precut wire mesh and cover the second pot. Bend the edges of the wire mesh to hug the outside contours of the pot. Then carefully invert the pot and place it atop the first pot so both pots are joined evenly.
  6. Take the clay and mould it around the join of the pots with approx. 20mm overlap from the join with a 20mm thick layer all around, ensuring clay adheres to the pot and is pressed onto the join of the pots.
  7. Then create a teepee structure with the firewood over the entire pot. Use some kindling to help with starting the fire. Once the firewood is stacked, light the firewood and let burn for two hours. Replenish the firewood as it burns down, continually tending the coals to keep the pots covered. After approx. two hours of burning, clear away the coals and remaining firewood and cover the pots with dirt in a mound like shape with an even 150mm layer all over. Pack down the dirt with the shovel, taking care not to disturb the pots.
  8. Let the pots rest for 24 hours and bake residual heat in the mounded dirt.
  9. After 24 hours, carefully remove all the dirt from around the pots. Be careful not to disturb the pots’ seal of clay. Then chip away at the baked clay and fully remove it from the pots’ seal. Once removed, broom away any further loose dirt to avoid it entering the pot chamber. Then carefully lift the top pot away from the bottom pot. Put top pot aside as it is no longer needed. Inspect the contents of the bottom pot. This is the remnant of marrow, meat and fat. It could range from dark to light coloured sludge. It should smell awful.
  10. Pour contents of bottom pot into a jar for storage and take care not to spill any on clothing, as the smell tends to stay with you.

On reflection, we could have burnt the fire for longer to render down the sauce further, as it did not quite look like the sauce in Sepp’s video. We may not have considered that pine timber (may have been used in Sepp’s video) burns hotter than the blue gum and stringy bark we used. Nonetheless, it is similar to other results I have seen since. We might be onto a winner. We will observe the trees in the future and see what the possums do. As this is all research, we need to try and retry until the results are conclusive. There could be a few late nights.

We are eager and getting ready for our next filming gig on the farm.

Further Reading:

8 Comments

  1. This is pretty exciting for me as we live up north in Tassie and are plagued by possums. We have just fenced off the area around the house and we have 2 dogs that are able to access this area so hopefully the small orchard contained inside the perimeter of this new fence will be spared the mangling it gets on a regular basis by possums but we have other fruit trees, outside this perimeter that are regularly invaded and branches snapped, fruit eaten before it is even ripe and a lot of damage through leaves being eaten. Before we moved here we thought that possums were cute. Now we know better. I am going to try this bone sauce. I hope it works as there is no way that we penniless student hippies are able to fund fencing the entire 4 acres we own. Cheers for an excellent idea and a chance at hope.

  2. G’day narf77,

    thanks for your encouragement on the info in the video. If Zepp say’s it work then its good enough for me. I will however continue to watch with anticipation for results. I really want to eat those Peaches this year.
    Cheers,
    Paul

  3. Have you thought of using a pressure cooker? What about cooking at pressure for 2 hours then perhaps at a lower heat for 20 hours, or wrapping it in something insulating? I am always looking for the easy way…

  4. If this works mate you’ve got pure gold. Possums are the bane of many a Tassie grower. I reckon a few folk in NZ may like this too.

  5. I’m a NZ folk who definitely likes it. We’ve been contemplating a fence with electric wire around the top but we have mixed opinions from our local pest control people about whether it will work. In the meantime, the season is approaching and no fence so I think this is worth a try. There will be trees outside any future fence anyway so now I’m on the hunt for two matching dutch ovens. :-) Thanks.

  6. Hello Paul

    In the UK I use aluminium lithographic plates (thin aluminium sheet) wrapped around my walnut trees to prevent squirrels taking the nuts. I secure the sheets with brown parcel tape which easily lasts from August to November (the time when the nuts are vulnerable to squirrels), and can last up to eight months if I forget to remove a sheet. It works by preventing the squirrels claws getting a grip on the trunk. The trunk of the tree does have to be of at least 100mm diameter to prevent the squirrel from hugging the guard and getting up that way. I think possums are larger than grey squirrels so a wider tree trunk may be require for the aluminium guards to work. Also I keep the crowns of my trees at least 1.5m of the ground, and keep a distance of at least 2m and preferably three metres between trees to prevent access by jumping. I sourced my lithographic plates from a local scrap metal dealer and a friend in the printing trade. I hope my this is of help to you and other.

    Thanks for the bone sauce recipe.

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