[Pil-pc-oceania] Hydroponics and technology in Permaculture

[pacific-edge]

Thanks for your response Graeme. I think a conversation around hydroponic
systems, organic or otherwise, and their application to rooftop food
production and application elsewhere in metropolitan cities is beneficial
because it explores the potential of such systems and helps us clarify our
own ideas. I have a couple comments on a few of yours ideas.

Are you talking about the West Australian greywater system that appears in
Josh Byrne¹s organic gardening video? This is somewhat complex, from what I
recall of my single viewing of the DVD, though he did stress the need for a
plumber to install the thing. I didn¹t see the ABC broadcast of the story as
we are two of the one per cent of Australians without television (I get most
of my news from online sources and radio and by downloading podcasts of
radio programs).

My thoughts on ¹approved¹ or off-the-shelf models of things like greywater
systems is that they are more accessible to time-poor and
lacking-in-manual-skills suburban people. By way of analogy, the
availability of enclosed compost bins made composting a viable option for
even small households, many of which would not have been attracted to or had
space for open compost bay systems. Likewise, the availability of
off-the-shelf worm farms brought composting to apartment dwellers. This we
learned when running organic gardening courses for Eastern Suburbs Community
College (Sydney) and which Fiona has found while running sustainable urban
living courses for Randwick City Council.

I agree that, where a building 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, as you suggest, could be more useful. Rooftop gardens are few
in Sydney but many apartment blocks ­ not only the newer but those going
back to the 1930s - use the roof for social space, which is, of course,
quite valuable as it facilitates positive social interaction and
conviviality. Both are important in cities and both have been somewhat
ignored in Permaculture education. I am sure that designers could
incorporate PV panels with this type of use of space. Maybe, with current
development at the King Island (Bass Strait) wind farm of a new type of
battery ­ a vanadium flow battery (the King Island facility, while serving
R&D, is operational and provides energy to the island, reducing the emission
of carbon dioxide from the island¹s diesel generator by 2000 tons a year- a
battery that can store PV and wind (and any other renewable) energy, perhaps
another use for urban rooftops will eventuate.

Most urban areas, you say, have thousands of acres of vacant land - lawns,
nature strips, road and railway verges, under-utilised park land, and that
these could be used for growing food naturally without spending large
amounts of money and resources into the intensive growing of food
hydroponically, on the Œrooftops of structurally-unsound¹ buildings.

Not all buildings with rooftop garden potential are structurally unsound.
True, there are thousands of hectares of Œvacant¹ land in cities. What we
found in the 1990s, though, while a team of us were searching for land for a
CERES-replication, was that much land is unsuitable for growing, some, as we
found, being contaminated by previous landuses. As for places like rail
verges, I have seen only two vegetable gardens by the rail tracks and they
disappeared long ago. Such places are off-limits because of safety concerns
­ high speed trains and gardeners in close proximity don¹t mix well. There
certainly is underutilised potential for food production gardens in some
parks and a number of community gardens have been set up in parks while the
park, as a whole, has remained as a multiple-use facility. As for road
verges, there is also potential as the examples of the use of macadamias as
street trees in Brisbane and bush food trees in Sydney demonstrate. A number
of gardeners in Sydney have made use of their footpaths for growing food
while leaving plenty of space for pedestrians.

You say: ŒThe 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.¹

That happens to soil-based farms, too, when infrastructure and inputs become
unavailable.

ŒSuch 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 Œfree¹. 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.¹

Speaking generally, we are only ahead in a thermodynamic sense if we
eventually obtain greater energy from a system than goes into its
construction, operation and ongoing inputs. Realising such gain may take
some time but that should not be a difficulty as nature operates over deep
time. So, using non-renewable materials and energy to eventually produce
greater outputs might not be a problem. That¹s how we use photovoltaics, for
instance. The residence on the land next to the old cottage, as well as the
cottage in which we live, uses an electric pump to serve the buildings with
water that is collected in the 27,000 litre rainwater tank (they are
probably the only mains-disconnected dwellings in Manly). This, of course,
uses energy (though that is partly offset by selling energy from the house¹s
rooftop PV array to the energy supplier) but that use surely is offset by
the gains in water conservation.

As for food quality, I¹ve seen no assessment or hydroponic versus
soil-grown, so I¹ve no information to comment on that. Nor do I have any
argument with Bill¹s schematics on the Permaculture versus industrial
production of eggs, however I think the question of hydroponics in high
density population/limited land availability urban situations should remain
an an open question. Tom¹s ideas on Aquaponics is one reason why this should
be so. One reason is that this year, according to the UN, our global
civilisations cease to be predominately rural-based ­ humanity becomes a
mainly urban species (though that¹s always been the situation in Australia).

The question ­ and dilemma, for many ­ of new, high-tech materials and
systems such as hydroponics that have potential environmental benefit is
going to grow, which is why discussions such as this are important.
Photovoltaic glass, for instance, is one such new material, as is an energy
producing fabric based on solar energy. This gets to David Holmgren¹s
critique off what he calls Œgreen technology¹ (which he recently delivered
during his peak oil presentation), however David¹s critique is not
universally shared among sustainability advocates. Some see validity in what
he says but disagree on aspects of the green technology question. This is
not to say that what David says is not true, but that, rather, many see
green technology having a very important role to play in sustainable
societies. Even Dr Ted Trainer, when I used to tutor for him at UNSW,
acknowledged the potential role of green technology and, consequently, the
important role of science in sustainability.

Another aspect of the technology question is that our attitudes and
practices change as new information becomes available. Perhaps I can lapse
way back to an example dating from the early 1970s, probably before some
readers were born, when the materials question became a discussion point
even then. In question was the popularisation of polymath, Buckminister
Fuller¹s geodesic dome and its utility as simple, affordable shelter,
especially on intentional communities of the time. An initial school of
thought believed that synthetic covering materials were desirable because
they avoided the unsustainable harvesting of forests for building materials
for the domes. Then, within a short time, attitudes changed when it became
apparent that there were environmental costs associated with this,
especially pollution. It was the availability of new information which led
to reappraisal of existing beliefs. Maybe, in some ways, this will relate to
green technology, though in what way remains to bee seen.

Anyway, thanks for the conversation and let¹s keep it going from time to
time as the technology question is not going to go away.

...Russ Grayson


From: Graeme George - Earthcare Permaculture <earthcarepc at virtual.net.au>
Date: Tue, 16 Jan 2007 16:47:29 +1100
To: pil <pil-pc-oceania at lists.permacultureinternational.org>
Subject: Re: [Pil-pc-oceania] Hydroponics

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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