[Pil-pc-oceania] Hydroponics

[Graeme George - Earthcare Permaculture]

Dear Russ

Thanks for your perspective on hydroponics.  I suspect that the reduced 
level of debate about these issues may be due to many in the 
permaculture movement being seduced by the glamour of  high-tech 
solutions to basic problems. We've see this on the ABC's Gardening 
Australia, where an "approved" grey-water treatment system, with all 
it's gadgetry, was broadcast by one of our own as being the 
"permaculture" way of gardening.

With regard to rooftop gardening. On a farm one would undertake a land 
systems capability assessment before deciding what purposes to put a 
particular parcel of land to. Why is it any different on a city 
roof-top? If a structure won't support a roof-top garden then one should 
find another use for the space, not force a garden solution. An array of 
PV panels would be more useful.  Most urban areas have thousands of 
acres of vacant land, urban lawns, nature strips, road and railway 
verges, under-utilised park land, etc, that could be used for growing 
food naturally without throwing heaps of money and resources into the 
intensive growing of food artificially on the rooftops of 
structurally-unsound buildings.

The concept of /Permitted and forced functions/ (Mollison 1988, pp 
31-32) could be extended to the rooftop gardening situation.  Food 
plants growing in an artificial medium are totally dependent on the 
infrastructure and inputs to produce a yield with a high probability of 
collapse if one of these fails.

Such artificial systems use up non-renewable resources, heaps of 
embodied energy in the manufacture of their components and  nutrient 
inputs, and more energy to run them.  Even a PV array running a pump 
requires resources and energy for its manufacture, with a long pay-back 
period before the electricity becomes "free". Where is the nett energy 
gain in such technologically-based systems? Niree and Linda have 
mentioned the food quality issue, so I don't need to elaborate on that.

I  see hydroponic systems of growing vegetables in the same class as 
factory farming of animals to produce meat and eggs. In teaching the 
concept of embodied energy I find two diagrams from the Designer's 
Manual to be very useful - The Industrial method of Producing an Egg and 
the Permaculture Way (pp 24-25) - they say it all.

I'll comment separately on Tom's aquaponics.

Regards

Graeme


pacific-edge wrote:
> Hi Graeme...
> Just got back from Queensland and found your email.
>
> You are right that hydropononics has been criticised in Permaculture circles
> on account of the artificiality of the culture of plants within it and on
> account of the greater energy expenditure involved. The question used to
> come up for discussion in courses. This was some time ago. I do not know
> whether that critique is so strongly held today.
>
> If it is less-strongly held, that could be related to the interest in the
> potential of hydroponics in urban agriculture, to cities feeding themselves.
> As you may know, hydroponics may have application as a form of rooftop
> garden agriculture. Soil-based growing might not suit rooftop cultivation
> where the building structure is unsuitable due to the weight of moist
> growing medium and equipment. In rooftop hydroponics, the pumping energy
> needed to circulate the plant nutrients in solution may be derived from
> photovoltaic electrical energy and in cold climates the hydroponic farm may
> be enclosed in a greenhouse. Furthermore, a method of organic hydroponic
> cultivation has been developed, though I no longer have the reference to
> that.
>
> Of interest might be the early work of the Todds. They experimented in
> integrated water cleansing, fish and food growing in their Ark building in
> the US. This was done in an enclosed greenhouse-type structure, though this
> was an accommodation to the cold climate. It was an exercise in the
> downstream utilisation of the wastes of preceding processes.
>
> ...Russ
>
>
>
> From: pil-pc-oceania-bounces at lists.permacultureinternational.org
> [mailto:pil-pc-oceania-bounces at lists.permacultureinternational.org] On
> Behalf Of Graeme George - Earthcare Permaculture
> Sent: Saturday, 6 January 2007 4:55 PM
> To: pil-pc-oceania at lists.permacultureinternational.org
> Subject: Re: [Pil-pc-oceania] Aeroponics
>  
> Penny & Tom
>
> I'm curious to know where you see hydroponic, aquaponic and aeroponic
> systems fitting in with Permaculture. I've always viewed Permaculture
> systems of growing food as being totally natural and hydroponic systems as
> being totally artificial, though I know many people curiously confuse the
> two. I have presumed until Penny's latest posting that aquaponics and
> aeroponics sat somewhere between these totally opposed systems, but the
> additional step of spraying solution onto bare roots would require
> additional energy expenditure and therefore make them even less sustainable.
> I don't see how these modified hydroponic systems can be seen as a part of a
> Permaculture solution.
>
> Regards
>
> Graeme
>
> Graeme George
> Earthcare Permaculture
> 35 Deering Ave, Healesville, Vic, 3777
> (03) 5962 5070
>
>
>   

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