for the horticultural industry
December 2012 - January 2013
The development of LEDs for
horticultural production applications
is moving fast, and there are now
several examples of commercially-
available LED lights that manufacturers
have developed specifically for the
horticultural market.
A number of progressive horticultural
companies are already investing in these
products and techniques, so does this mean
that LEDs already make economic sense?
To get an insight into the current economics
of LEDs, HDC commissioned a project (ref.
PO 010) with Farm Energy Centre to look at
how the capital and running costs of LEDs
compare to conventional lighting.
A set of example installations were
investigated as part of a desk-based study.
The applications investigated were:
• Photoperiodic lighting
– where LEDs
are used as a replacement for tungsten
lighting over flowering crops, soft fruit
• Young plant lighting
– here, the LEDs
are used to replace fluorescent tubes
in growing rooms or on multilayer
benches in greenhouses.
• Inter-crop lighting
– here, arrays of
LEDs are placed deep in the crop
canopy to stimulate activity from the
parts of the plants that are shaded
in traditional production systems.
Applications are in both the ornamental
and edible protected crops sector, with
cut flowers and vine crops (e.g. tomato)
being the most suitable.
Growers get the latest thinking on LEDs
development have progressed, it has come
to be accepted that energy saving is only
part of the picture. Project PO 010 further
reinforces this and quantifies what cropping
improvements need to be worth to make an
LED installation cost effective.
Sharing knowledge and
At HDC’s ‘Focus on Light Spectrum’
Event on 4th December at Stockbridge
Technology Centre (STC), issues
surrounding how lighting plants can
change plant performance, as well as drive
photosynthesis, was explored.
Growers discovered the latest thinking
on how specific wavelengths of light can
manipulate plant shape, colour of leaves
and flowers, rooting, chemical composition
and timing of flowering, and attracting pests
out of crops and preventing disease spread.
A number of short presentations were given
at the event by researchers, consultants
and growers, and the audience had the
chance to hear first-hand the experiences
of some of the early adopters of LEDs and
spectral filters. Delegates could also view
Stockbridge Technology Centre’s new ‘LED4
Crops’ facility – a new resource that the
industry can use to develop successful
applications of LED lighting techniques.
For the report on Project PO 010 and the
presentation from the Light Spectrum event,
see the HDC website:
The results revealed that young plant
lighting is the most economically viable.
Where the LEDs are used to replace tubular
fluorescent lamps, paybacks of five years or
less are achievable. Also, moving to multi-
tier growing—with LEDs being used to light
the crops on the lower benches—can make
economic sense, as it allows better space
utilisation in the greenhouse.
With the other two applications, the
economics are not as clear cut, and
paybacks of less than five years can only
be achieved if the energy saving features
of LEDs can be supplemented by cropping
improvements, such as better quality, more
yield, and less disease.
When the concept of using LEDs for
horticultural crop lighting was first mooted,
much of the talk was about their energy
saving advantages and the promise that
they could slash the energy consumption
and running costs of lighting installations.
However, as LED knowledge and hardware
Energy market update
We’ve seen a rise of just over 10% in the wholesale cost of gas and electricity and
the cost of crude oil has steadily increased. Political unrest is perhaps the biggest
determining factor, and the continuing turmoil in the Middle East is making things
particularly nervous.
The availability of energy from renewable generators is now also starting to become a
key factor in determining wholesale energy prices, particularly in the short-term markets.
Overall, the analysts are predicting continuing energy price inflation, so prepare your
buying strategy and energy budgets with this in mind.
Multi-tier lighting using LEDs as an alternative to tubular fluorescent lighting can give paybacks of five years or less
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