Lesson 2 - Know the environment provided by a range of protected structures Flashcards
describe the temperature differences between the protected environment and the outdoors
Protected environments provide frost free winter protection and can provide shade in the summer.
Heating systems can increase greenhouse temperatures.
Increased ventilation, damping down and shading can lower temperatures.
Temperature indoors can be manipulated to fit the needs of the plants being grown so they can develop normally at any time of year.
describe the humidity differences between protected environments and the outdoors
Protected environments need damping down to provide humidity in summer. Air movement is important to keep humidity down, but restricting air flow will up the humidity. This means the protected environment can be altered to fit the plants needs.
Warmer temperature air can hold more humidity than lower temperature air.
Describe the differences between the protected environments and the outdoors in relation to light
Supplementary lighting may be required in protected environments and this lighting may need replacing over time. Day length and quality of light can be artificially controlled inside.
Shading may be required in the summer to reduce the temperature of the structure. This reduces light to the plants.
Obstacles outside of the structure may provide shade.
Describe the difference in the concentration of atmospheric gases in protected environments and the outdoors
The availability of carbon dioxide may become a limiting factor in photosynthesis in protected environments. Carbon dioxide can be enriched artificially when growing commercially using carbon dioxide burners. At home, opening the vents of the greenhouse should suffice.
Describe the differences of air movement in protected environments as opposed to the outdoors
Ventilation by natural air movement in the structure. Forced draughts or fan ventilation can be used to control the air movement for humidity control and to minimise disease transmission.
Describe the environmental differences between the protected environment and outdoors in regards to irrigation requirements
Overhead watering and sub-irrigation for crops grown in containers and in the border soil.
Protective structures prevent natural rainfall from getting to where the plants roots.
Handwatering and capillary tray systems can be used.
state the benefits of using protected structures for growing plants, for example, tomato, Lycopersion esculentum, compared with growing the same crop outdoors
Higher yields and quality, longer season of fruiting and ripening, can grow a greater range of cultivars
Greenhouses can be sterilised when not n use to reduce pests and diseases. Biological control methods however, can be more effective in protected structures than outdoors.Using chemicals in a greenhouse may result in little impact on the immediate external environment.
state the limitations of using protected structures for growing plants, for examples tomato, Lycopersion esculentum, compared with growing the same crop outdoors
Relative costs, effort required, different pest and disease problems indoors.
Pest life cycles are accelerated as the temperature increases in the greenhouse, meaning more reproductive cycles and therefore more pests.
