2102 - Hydroponics & Water Culture

Question 1

What is Hydroponics

Answer 1

A form of plant cultivation where the roots of the plant grow in water with a complete nutrient solution dissolved into it.
Either without a solid growing medium, or an insert one (rock wool).

Question 2

Situations where hydroponics is used….

Answer 2

Commercial crop production - tomatoes, cucumbers, lettuce

interior landscape displays

some green walls

Question 3

Nutrient Film Technique

Answer 3

Method of growing plants in a shallow stream of nutrient solution, continuously circulating in shallow gullies or troughs.

• A form of hydroponics used for glasshouse salad crops.
• plants are grown with the roots in a shallow stream of water and nutrient solute, which circulates continuously.
• no solid rooting medium, mass of roots develop
  (shallow moving water = fresh oxygen supply)
• Nutrient, pH and salinity monitored and maintained

Question 4

Substrate (aggregate) culture

Answer 4

• Similar to Nutrient Film Technique but inert rooting medium is used
• rockwool blocks used to contain roots, water dripped onto the blocks
• effect made to recirculate the water but it is often dumped, or used to irrigate outdoor crops

Rock wool:

• light, inert and sterile
• good aeration and moisture retention
• low/none nutrient levels, retention.
• very energy intensive to produce
• not reusable, landfill

Question 5

Hydroponics advantages

Answer 5

• reduction in soil borne disease
• reduction in labour costs (after set up)
• reduction in growing medium cost
• high growth potential

Question 6

Hydroponics disadvantages

Answer 6

• disease can spread rapidly to other plants
• continuous nutrient, pH, salinity content to be monitored
• high set up costs
• some systems can lack oxygen to roots
• wasteful of material (rock wool) and water
• very energy intensive and environmentally unsustainable