I want to reuse and recover as much as I can in my kitchen and gardening activities. So it is only natural that I wondered what I could do with the bones left over after cooking. Some of them go into my worm farms but as my young family is eating more and more meat every day that is only a part solution :).
Some happy Googling later I came across lots of websites showing you how to make home made blood and bone meal. Using blood and bone meal to improve soil is as old as time due to its slow release of nitrogen and phosphorous. For those nutrients to be available to plants though requires slightly acidic soil and I find (even here in Perth) that my “improved” garden beds always meet that requirement.
One of my favourite television shows and websites (Gardening Australia) also informed me that blood and bone meal has a complete lack of potassium. So I added a small amount of potash as they suggested. See http://www.abc.net.au/gardening/stories/s1503292.htm.
Most of the bones I am using have already been cooked once and then recovered to make stock (see my chicken stock post here) and are hence nice and clean. I then bake them on low for a few hours and I do this in my Weber after cooking a roast. I don’t waste any fossil fuels.
This makes them hygienic and brittle enough to break apart in your hands. When I have enough of a collection I feed them through a corn grinder and store the meal until I need it.
This is the clean bones being baked and stored:
- has variable sized particles (great for varying the release of the nitrogen, phosphorous and calcium)
- has almost no aroma bar a mild earthy smell
- stores well in a sealed dry container.
As I mentioned above, I also add a small amount of potash granules to the meal to counter the lack of potassium. We now have everything we need for healthy plant roots, bodies, fruits and metabolism.
Of course, be careful when dealing with any soil improvement medium. We have a strict hand washing policy after gardening and also carefully rinse all produce. I wouldn’t put anything in my garden that I was the least bit worried about and neither should you.