Explain the considerations required when growing plants in water culture.

State what is meant by the term hydroponics.

WATER CULTURE see hydroponics Food Production: Particularly tomatoes cucumbers pepper and salad crops. Green Walls: Interior Landscaping:

Identify the environmental implications of growing plants in water culture.

Useful where area for production is small; Useful in areas of limited soil; Uses as little as 10% of water a soil-grown crop would need; As it is possible to grow crops anywhere, there are likely to be less food miles involved therefore less CO2 impact; Growhouses in inner London and New York Cost of production means only high-value crops are grown; or quick turnover High system set up costs (cheap in the long run); Rock wool is indestructible and cannot be reused or recycled, it must go to land fill; Energy/cost of material/chemical production. Cannot survive without skilled staff to set up and monitor, Would not work when irregular electricity or main water. Usually linked to controlled lighting and heating.

HYDROPONICS “Growing plants in water culture”. There are 2 common methods NFT (nutrient film technique) and substrate culture (rock wool); Widely used in the commercial production of salad crops under glass. Water Quality: Good clean water supply required (tap); This is filtered as it circulates and passed through an ultra violet light tube to control pathogens and algae growth.

Pest/Disease Control (water quality/pathogens): As the whole system is very intensive in many ways (for maximum growth) everything is geared up – maximum solution/correct pH/high growing temperature/high light intensity. If anything goes wrong it can quickly spread and the whole crop lost very quickly (a waterborne pathogen can be circulated through the whole crop in a matter of hours). It is usual to use preventative rather than creative measures. Automation of the system is possible.

Aeration, nutrient supply, nutrient levels and pH control, water supply and quality, pest and disease control, automation.

AERATION (HYDROPONICS) NFT rely on the water film where the roots grow thin and so are well aerated; Rock wool growbags drain so not becoming water logged; Some commercial systems will make use of an air pump in the solution tank to ensure the solution is saturated with oxygen.

NUTRIENTS (HYDROPONICS) ALL minerals needed by the crop are supplied in a solution; Differing solutions are used to suit the crop/stages of growth/often recycled; Changed periodically. These are very closely monitored and altered/topped up as required/ changed periodically; Ideally maintained at 21ºC.

PH (HYDROPONICS) The ideal pH for the solution is between 5.5-6.5 for mineral availability. This is adjusted as required by the addition of proprietary products (pH up/pH down).

Describe TWO methods of growing plants in water culture, to include: NFT (nutrient film technique), substrate culture (rockwool).

NFT (ACRONYM) nutrient-film-technique

NUTRIENT FILM TECHNIQUE Widely used in the commercial production of salad crops under glass.

NFT Plants are held in growing channels and the nutrient solution is introduced at the top of a gentle slope, this then passes down, passing or washing the roots of the crop. It is collected at the bottom and recirculated back to the header tank.

SUBSTRATE CULTURE Rock Wool/Substrate Culture: With this method the crop is grown in grow bags containing a root zone of rock wool and the nutrient solution dripped on to the rock wool. Ideally the rate of drip is regulated so there is little drainage from the bag.

ROCKWOOL

CLAY PEBBLE

CANNA

EBB AND FLOW

State the situations in which water culture can be used, to include: green walls, vegetable production (tomatoes), interior landscaping. Identify the environmental implications of growing plants in water culture.

WATER CULTURE see hydroponics Food Production: Particularly tomatoes cucumbers pepper and salad crops. Green Walls: Interior Landscaping:

Identify the environmental implications of growing plants in water culture.

Useful where area for production is small; Useful in areas of limited soil; Uses as little as 10% of water a soil-grown crop would need; As it is possible to grow crops anywhere, there are likely to be less food miles involved therefore less CO2 impact; Growhouses in inner London and New York Cost of production means only high-value crops are grown; or quick turnover High system set up costs (cheap in the long run); Rock wool is indestructible and cannot be reused or recycled, it must go to land fill; Energy/cost of material/chemical production. Cannot survive without skilled staff to set up and monitor, Would not work when irregular electricity or main water. Usually linked to controlled lighting and heating.

WATER CULTURE see hydroponics Food Production: Particularly tomatoes cucumbers pepper and salad crops. Green Walls: Interior Landscaping:

Identify the environmental implications of growing plants in water culture.

Useful where area for production is small; Useful in areas of limited soil; Uses as little as 10% of water a soil-grown crop would need; As it is possible to grow crops anywhere, there are likely to be less food miles involved therefore less CO2 impact; Growhouses in inner London and New York Cost of production means only high-value crops are grown; or quick turnover High system set up costs (cheap in the long run); Rock wool is indestructible and cannot be reused or recycled, it must go to land fill; Energy/cost of material/chemical production. Cannot survive without skilled staff to set up and monitor, Would not work when irregular electricity or main water. Usually linked to controlled lighting and heating.