Plant and Soil Science
Introduction to Hydroponics
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What is hydroponics?
• The word hydroponics is derived from
the Greek words “hydro” and “ponos”
• It is the science of growing plants in an
inert medium
• Nutrients come from a nutrient
solution
2
Commercial use of hydroponics
• It has been used in the
industry for over 45
years
3
Crops
• Almost any herbaceous plant
• lettuce, tomatoes, peppers,
cucumbers, and herbs
• The crops that are grown are
usually specially bred for
hydroponics
4
Advantages of hydroponics
• It can be used regardless of soil type
• Fresh produce can be grown all year round
• Crop yields are higher with hydroponics
compared to conventional methods
• Higher quality product can be produced
• Soil borne insect and disease problems are
greatly reduced
5
Advantages of hydroponics
• Since there is no soil, there is no need to
cultivate or weed the crops
• Less pesticides are used because the crops
are so healthy
• All plants receive the correct nutrients at the
right time
• Hydroponics allows for greater efficiency of
water and fertilizers
6
Disadvantages of hydroponics
• High start up cost
• Operators need to be skilled
• The system must be sanitary
and kept clean because
disease can affect all plants if
it gets into the solution
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Hydroponic methods
• Water culture
• Aggregate culture
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Water culture
• Nutrient film technique
(NFT)
• Aeroponics
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Nutrient Film Technique (NFT)
• Plants are grown with their roots in a
trough that water runs through
continuously
• Water level is very shallow to allow
adequate air exchange
• Troughs can be up to 100 feet long
and are sloped about two or three
degrees to allow the water to flow
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NFT
Nutrient Film
Technique
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Aeroponics
• The roots of the plant are
suspended in a chamber where
the roots are misted constantly.
• The chamber creates an
environment in which there is
100 percent humidity
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Aeroponics
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Aggregate culture
•
•
•
•
Gravel culture
Sand culture
Sawdust culture
Other cultures
–Common: rockwool culture
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Hydroponics
15
Gravel culture
• There are beds that are filled with
gravel
• Plants are placed in the gravel
• The plants are irrigated through
sub-irrigation.
• The number of irritations depends
on temperature and size of plants.
16
Sand culture
• There are beds that are filled with
sand
• The beds can be on benches or on
the floor
• Plants are placed in the sand
• The plants are watered through
drip irrigation that brings water and
nutrients
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Sand culture
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Sawdust culture
• Similar to sand culture
• Sawdust from Douglas fir and
western hemlock give the best
growing results
• Medium sized particles are the
best size to use
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Rockwool culture
• Rockwool is one of the most widely
used mediums. Almost all the plants
that are used in the other aggregate
cultures were started in a rockwool
cube
• Rockwool can be reused for three or
four years
• Drip irrigation is usually used with it
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Rockwool
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