4. Incandescent Lamps
Poor light quality
High heat load
Low efficiency (7%)
Too much light in Red
Far red range
5.
6. Fluorescent Lamps
Commonly used over
small growing areas
(germination)
Rare for finishing crops
More efficient (20%)
Low wattage, so you need
a lot of them (shadow
creation)
7.
8. HID/High Pressure Mercury-Type
Mostly replaced by Metal Halide lamps
Similar spectrum to fluorescent lights
13% efficiency
Up to 1000 W; can last over 10,000 hours
Also used to light roadways
9.
10. HID/Metal-halide type
Up to 2000 W
20% efficiency
More expensive than Mercury types, and
have a shorter life
11.
12.
13. HID/ Low Pressure Sodium
Very narrow band at 589 nm
Little in the 700-850 nm range
Low level of blue lights
Some success in combining
with incandescents
In Northern areas can affect
leaf morphology
Large reflectors cause shadows
14.
15. HID/ High Pressure Sodium
Life expectancy of up to 24,000 hours (2.75
years)
Cheaper to purchase
Better spectrum than LPS
Most common worldwide today
25% efficiency !!
For some crops extended light spectrum
results in increased fresh weight, stem
elongation, and early flowering.
19. Supplemental Lighting
Already common above 40ºN latitude in U.S. and
50ºN latitude in EU
Gaining popularity in south
Especially profitable in winter months
Cost about $2.90/ft2 of growing space (HPS)
Chrysanthemum, geranium, begonia, rose, and
plugs
300 – 600 fc for ornamentals 600-1000 fc for
vegetable crops
20. Other Notes:
Use only horticultural fixtures – reflectors
important
Reflectors for different locations in the
greenhouse
Usually 16-18 photoperiod used
Higher plant densities are more economic.