1

Plant and Soil Science

Introduction to Hydroponics

2

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

3

Commercial use of hydroponics

•It has been used in the industry for over 45 years

4

Crops• Almost any herbaceous plant

• lettuce, tomatoes, peppers, cucumbers, and herbs

• The crops that are grown are usually specially bred for hydroponics

5

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

6

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

7

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

8

Hydroponic methods

• Water culture

• Aggregate culture

9

Water culture

• Nutrient film technique (NFT)

• Aeroponics

10

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

11

NFTNutrient Film

Technique

12

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

13

Aeroponics

14

Aggregate culture

• Gravel culture

• Sand culture

• Sawdust culture

• Other cultures

–Common: rockwool culture

15

Hydroponics

16

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.

17

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

18

Sand culture

19

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

20

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

21

Rockwool