Hello,
I’m a French journalism student in Paris, researching urban
agriculture and vertical farming projects that incorporate
hydroponics and aeroponics. What do you think about these
vertical farm projects? Do you think that they are utopian?
What are the advantages and the drawbacks of hydroponics
and aeroponics? How does the quality of hydroponic/
aeroponic crops compare to crops cultivated outside in soil?
Thank you for your time.
Kind regards,
Thibaut Forté
The future of agriculture is becoming a very interesting conversation as
farmers around the world struggle with
more volatile weather conditions while
feeding a growing population. There
are many facets to the changing face
of agriculture, and vertical farming is
one of them. The concept of layered
farming within a building is an efficient
and creative opportunity. Vertical farms
require supplemental lighting to ensure
the plants in the middle are receiving
the light required for healthy growth.
This adds a large energy component
to the project and the more floors
there are, the more energy needed.
LED lighting options might provide
an alterative, but not for vining crops
such as cucumbers and tomatoes, which
are two of the dominant crops grown
hydroponically in the world. In the
short to medium term, we should look
at low cost, low input models before
jumping into the high cost, high input
option of dedicated structures for urban agriculture.
Using rooftops we already have is
a good first step towards sustainable
urban food production. There are a
couple of problems when it comes
to water-based roof gardens. The first
problem is the amount of radiant heat
on rooftops; this can make water temperature regulation a massive issue, especially in sensitive aeroponic systems.
Also, the waste water from hydroponic
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Maximum Yield USA | July 2011
systems still has a vast amount of
soluble nutrients unused by the plants.
This creates an issue of disposal.
Fresh substrate would also need to be
brought in between crops. Most large
green roofs currently use drought-tolerant species that are planted and then
basically forgotten. Now imagine the
same space including people interacting with food crops.
“Building food and
biodiversity into a system
that improves the urban
environment at the same
time would be such a
positive step forward.
”
An amazing first step in our urban
food development would be to take
the Cuban organoponicos concept and
place it on rooftops full of shallow (12
inch) raised beds filled with soilless
mix and compost. You would get the
insulation value, cooling effect and
water retention of a green roof along
with the low cost nearly self sufficient
aspect of the Cuban food experience.
Building food and biodiversity into a
system that improves the urban environment at the same time would
be such a positive step forward. Economically speaking, the building could
generate revenue by leasing this as an
additional floor and it would provide
opportunity for entrepreneurs looking
at food production but just needing the
space. A chance to get a new generation of people excited about farming?
That’s always a good thing.
In keeping with efficient urban farming and organoponicos, vermicomposting could supply the majority of nutrition in the soilless beds on the rooftop.
A building based on green diversion
could keep 30 per cent of building
waste on-site to build biodiversity and
feed the plants. A small portion of the
garden could also be dedicated to habitat for beneficial insects, improving the
balance of the space.
The vertical farm is a very creative
concept and will probably end up
being exceptionally important in the
future. Until we have worked out an
efficient system and a reasonable cost,
we need to adapt in different ways. Our
rooftops are numerous and can provide
nutritious, low impact food while reducing the heat island effect and making our cities more liveable. MY