Flushing out new composting ideas

September 29, 2009
Written by Gary Jones
In a previous “Inside View,” we looked at numerous options for making growing containers from renewable inputs. But what about the main item that fills those pots, namely the growing medium? Our staple for many years, peat, is a wonderful natural ingredient that has served (and continues to serve) the industry very well. It is estimated that 60 per cent of the world’s wetlands are peat bogs, and only seven per cent have been accessed for agriculture/forestry uses. A much higher proportion is simply burned as fuel.

But this isn’t the issue here.

Simply, are there untapped sustainable growing media for home gardeners? Here’s a couple of suggestions for discussion; some may raise some “eewww” responses, while others could elicit some … “he’s crazy” … comments.

The Langley Environmental Partnership Society (LEPS) has a demonstration garden used as a community educational tool. One of the main themes is composting, and there are numerous examples of “how-to-compost” projects set up in the garden.

From the output of green kitchen waste, leaf material from the vegetable patch and the occasional top-up of grass clippings (which are usually left on the lawn for the worms anyway) in my average suburban home, four people easily produce about two cubic yards of high quality compost per season. Rounding up, an average city of about 100,000 people could generate around 50,000 cubic yards. Put another way, about 2,800 dumptrucks and trailers’ worth! Add in all the high-carbon daily newspaper, two twice-weekly local freebie papers, junk mailings (minus high-ink glossy inserts), all the fallen leaf material, ashes from wood fires, and all other compostable materials, and this quantity will be considerably higher. Of course, it’s unlikely we’re even close to producing this amount in our town. And that’s probably because people don’t know how to do it, feel it’s too much work, or simply “don’t care.”

Perhaps there’s an opportunity here. People already run profitable businesses growing vegetables in a number of rented urban gardens in their neighbourhoods, the so-called “SPIN” gardening – Small Plot INtensive. What if some entrepreneur managed and “harvested” the compost from, say, 1,000 homes in a neighbourhood? That’s a fair pile of very valuable growing medium for use in gardens or indeed in the pots that grow plants in those homes. And this can be done close to the end users’ location – a sort of “100-mile diet” for potted plants. Clearly there would be some challenges (logistics, uniformity, economics maybe), but it’s a thought.

Now …  there has been some very interesting debate recently on the Certified Organic Association of B.C. (COABC) list-serve regarding the topic of the use of human waste as a manure source. “Humanure” is not a new concept, of course. The Hunza people of the Himalayas are known to use composted human waste and are the longest-lived people on the planet. Use of night-soil is still required in most rural communities in China. Many (all?) “organoponicos” in Cuba use composting toilets to supplement their crop nutritional needs.

There are inherent possible drawbacks: a potential for spreading liver flukes, heavy metal contamination, and the low nitrogen content of solid human waste – it’s mostly in our liquid waste! – for example. But properly composted, this option might provide a growing medium that’s not to be sniffed at and offers serious potential benefits. It:

Is renewable!

Is local.

Reduces garbage collection volume/cost.

Provides useful plant nutritional content.

Is a tremendous soil conditioner.

Would reduce the load on the urban sewage system, which simply uses valuable clean water as a transport medium for human and industrial waste, and in so leads to heavily contaminated toxic sludge.

OK, it’s not an attractive proposition to most people, nor to most (any?) municipalities, provincial or federal government departments. It’s not even permissible in certified organic production. But do we need to put aside our taboo and offer it more serious consideration?
Gary Jones is Chair of Production Horticulture at Kwantlen University, Langley, B.C. He sits on several industry committees and would welcome comments at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Questions or comments? Email greenhouse@annexweb.com

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