Since to operate. Incandescent lamps provided a

Since electrical lighting was developed, an artificial
lighting has been used as a replacement lighting, supplemental or
production lighting and photoperiod lighting. ( Argus cotrol, 2017). Plant
lighting technologies in horticulture took three general paths of development
(Withrow and Withrow, 1947 ). First, incandescent lighting, which was refined
by Edison’s invention of the incandescent filament lamp in 1879. Second, is the
fluorescent lamp. Third, in the late 1800, gaseous discharge lamps were
developed (Raymond, 2008).

            According the study conducted by
Siemens (1879), it shows that carbon arcs were probably the first lamps used to
grow plants in horticulture (Siemens. 1879). Carbon arcs provided an intense
point source with a broad, bluish spectrum and were still used for plant
testing through the 1940s (Parker and Borthwick, 1949). Carbon and hazards was
created from the emission of ultraviolet and exhaust products (Raymond, 2008).
However, if compared to the carbon arcs, incandescent filament lamps are much
more simple. It could be used up to 3000 hour if kept on continuously, and safe
to operate. Incandescent lamps provided a red biased light with a high amount
of far-red and infrared radiation, which produce heat and cause elongated stem
growth. In spite of that, Incandescent lamps are still used in
many plant growth chambers in combination with other lamps (Raymond, 2008).

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            In the 1930s, there is the
development of fluorescent lamps. The fluorescent lamp is a type of low
pressure mercury arc (Withrow and Withrow,1947). Unlike incandescent light,
which produced light by heating metal filament until it start to radiate light,
fluorescent produce light by exciting  of
low pressure mercury vapour in a mixture of inert gas and inside the surface of
the fluorescent tube, there is a phosphors coating that transform the ultraviolet
energy into visible light (Argus control, 2017; Withrow and Withrow, 1947 ).
Fluorescent lamps are more light efficient than incandescent lamps because it
provided a wide spectrum in photosynthetically active radiation ( PAR) range,
improved electrical efficiency, and a longer life span if compared with
incandescent lamps (Withrow and Withrow, 1947 ). Fluorescent lamp have provided
the ability to tailor the spectrum for plant growth and photobiological studies
(Raymond, 2008).

            Further testing with gaseous
discharge lamps, it similar to fluorescent lamps in that they introduce an
electrical arc into an elemental gas mixture. However, it differ from
fluorescent lamps because no fluorescing powders are used on the lamp glass, and the elemental
gases are heated under much higher vapor pressures and temperature. The two
most common discharge lamps used in modern horticulture are metal halide and
high pressure sodium lamps. Metal halide lamps use mercury vapor in a quartz
arc tube and various iodide mixtures of sodium, thorium, or thallium. They
provide the best overall spectral distribution of all horticultural lamps, but
are not quite as efficient in energy conversion as high-pressure sodium lamps
in the PAR range, particularly in the yellow-red spectra (Argus control, 2017).

            High pressure sodium (HPS) has
become the most popular lamp type as supplemental lighting in horticulture.
They are the most efficient in the PAR range with the exception of low pressure
sodium lamps. HPS have longer operating life, electrical efficiencies, and give
a wide spectrum light that was acceptable for a broad range of plant species
(Raymond, 2008). 
Metal halide lamps can provide strong blue spectrum (a spectrum that
tends to encourage leaf growth), experience rapid lumen depreciation due to
darkening of the arc tube and contain very high pressures which often require
the use of a lensed fixture. There have been attempts to combine the two into a
single lamp, but these lamps end up having a lumen maintenance imbalance, with
the blues of the metal halide depreciating more quickly than the high pressure
sodium components. Finally, as they require reflectors and can decay over time,
these sources become inefficient (Raymond, 2008).

            There have been few fundamental
development in plant lighting since high-pressure, arc discharge lamps and
finally Light-emitting diodes (LED). LEDs generate light through an
electroluminescent principle (Craford et al., 2001). LEDs are different from
other lamps used to promote the growth of plants. Horticultural industry are
interested in LEDs since the discovery was made that the spectrum of light
offered to plants can change plant properties, for example, can increase the
blossom and fruit growth rates, can improve photosynthetic
efficiency and so on. This is one the reason why LEDs lighting has become
an important technology for the viability of sustainable urban farming (Wilms,
2016). Today,
LEDs lighting can stimulate plant growth up to 40 percent (Wilms,
2016). LEDs are
also much more environmentally friendly compared to the other artificial light
that have been used in horticultural lighting, since it generate less heat.
Besides that, LEDs also provide a strong option for lighting for all types of
plants and flowers as its enabling the grower to adapt the light exactly to the
needs of various crops. It can be concluded, that the features of LEDs such as
a small form factor, numerous type of wavelength, energy saving, less heat
production, high efficiency and long lasting, have been made LEDs as a choices
in the horticulture lighting today  compared to commonly artificial light (Wilms,