Sawdust Bucket Composting

Greetings, Living Earth Gardeners! Last week we looked at Composting Toilet Systems in general. We noted that the composting of our own bodily wastes is an uncomfortable subject for many people, and this was acknowledged during the week. We revealed that there have been many different humanure composting systems developed that range widely in terms of complexity, cost, and user-involvement. We finished by considering that it is fairly safe and simple to begin with composting our own urine, even in a town situation. The book, Liquid Gold, bu Carol Steinfeld, shows various other ways in which to capture urine and then recycle its' nutrients for the benefit of plant growth.

Before moving on, allow me to note that although composting toilet systems are currently optional and voluntary, they are likely to become required of all of us in the future. Every time we flush a toilet, we are not only wasting good water, but we are also sending soil nutrients and organic matter out into our waterways, eventually, in most cases, to be deposited into our oceans. Those nutrients and organic matter need to go back into the soils that they were removed from. Current estimates, including those from the United Nations, predict that at present rates of soil depletion, we humans will have no farmable topsoil left on Earth in 30 to 60 years time.

Okay, having said that, let's move into the particular method of human manure composting that we have chosen to use here, at least for now. This method is known as the sawdust bucket system and is described in detail by Joseph Jenkins in his book, The Humanure Handbook: a guide to composting human manure. When starting on a land-based project, knowing what to do with our own bodily wastes can be an immediate barrier. In Wilderness Areas, we are directed to dig "cat holes", 6 or more inches down, and then cover our deposits thoroughly to keep wild animals from digging them back up (in their search for nutrients). Unless one has a very large tract of land, and is willing to walk to a different place each time these "cat holes" would soon accumulate beyond the ability of our land to absorb them.

The traditional toilet method on the homestead is the outhouse, or 'privy'. This is actually what I had in mind before we obtained our particular piece of land. I thought that we would simply dig a hole in the ground and put a toilet and outhouse on it. Then, when the hole was full, we would plant a tree over all those deposits to recapture the nutrients stored there, and move on to a new hole in a new spot. Our land is blessed with an abundance of groundwater. This groundwater makes possible plant growth that would otherwise be impossible in our high desert climate. High groundwater does make building more complicated, however, and one of those complications was that we had to dismiss this "outhouse/tree system" idea.

Although it did seem like a complication at the time, Joseph Jenkins shows through drawings that the old outhouse system was never all that good of an idea anyways. Unless the hole is lined and then pumped out, the pathogens in feces do leach into the surrounding soil, contaminating it both vertically and horizontally. This contamination happens in dry soil too, just not as broadly as in wet soil. The good news was that I had already been composting for 15 years, was familiar with a few different humanure systems from the farms I had worked on, and had recently taken part in a demonstration of this sawdust bucket system. I went ahead and read The Humanure Handbook thoroughly.

The sawdust bucket method is a simple system. First, we purchased a 'portable loo' by mail from a camping outfitter. They are made in Canada, but all it is essentially is a five-gallon bucket with a plastic seat and lid that snaps securely to the top rim. We then purchased some more five-gallon buckets with regular lids from the hardware store and gathered a large tubful of fresh sawdust from the local sawmill (to cover with one cupful each humanure deposit, whether solid or liquid, as well as giving each bucket and cupfuls at the bottom to start). We set up a small table and kept it supplied with toilet paper and alcohol-based hand sanitizer (which does not freeze in the cold weather). Later, we purchased another plastic toilet seat with lid in order to separate urine from feces (it is when the two are mixed together that the most disagreeable odors are created). By separating, the sawdust was able to absorb not only all of the liquid involved, but just about all of the odor as well.

As far as the 'privy/privacy' part of this composting outhouse system, we first put up a potty tent that was available through that camping outfitter, and as sunlight and wind degraded the nylon, we built strawbale walls on cement blocks around it with a wooden bond beam on top to keep the bales upright. A simple canvas tarp served as roof until it began breaking apart, at which point we replaced it with wooden slats. The doorway was left semi-open as it faced away from most activities and out onto 50 miles of open plateau with buttes and mountains on the horizon. All of this makes walking out to our 'composting potty' to make a 'time deposit' (with interest guaranteed)., a beautiful and unforgettable experience!

That is all anyone essentially needs to get started. While our approach reflects the realities of our land and climate, the underlying principles will remain the same anywhere. The outhouse structure, in particular, that we built around the toilets is well-suited for our high desert climate of  low rainfall, strong winds and extreme temperature swings. This kind of structure may be inappropriate, or need modification, in other bioregions.

Now, what to do with all the stuff in the buckets? Well, that is where some level of skill and knowledge are required. We will begin on that next week, when I will address Composting, both with humanure and with regular garden debris. As usual, please send us your questions.

With best wishes for this week!
Gardener Machei
Taos, New Mexico