Papers 6/14 Flashcards
Cold frame
Distinctive features
Low cost
Ideal for plant propagation
Limited height, lights can be removed once crops are established.
Polythene tunnel
Distinctive features
Lower cost than greenhouse
Heat retention properties not as good as greenhouse
Higher natural relative humidity - ideal for salad crops eg. lettuce and self blanching celery
Cloche
Distinctive features
Very low cost environment
Not possible to heat
Ideal for protecting row of plants or establishing plants such as beans
Protected structures suitable for decorative display of plants
Conservatory for indoor plants.
Alpine glasshouse for display of alpine plants
Benefits of growing tomatoes using a protected structure
Improved and controllable environment leads to increased yields and improved quality.
Longer cropping period i.e.extended season.
Opportunity to use biological control
Limitation of growing tomatoes using protected structure.
Cost of heating structure.
Pest and diseases can become more quickly established.
More care needs to be taken of crop
Less opportunity for natural pollination.
Two disorders that damage tomatoes
Blossom end rot - caused by calcium deficiency; young leaves become chlorotic, tomatoes turn brown and rot. Controlled by liming soil/growing media.
Splitting of tomatoes - caused by wet conditions followed by long dry period. Improving water retention of growing media and regular, careful irrigation.
Meaning of framework and cladding
Framework - main supporting structure of protected structure.
Cladding - material that covers or encloses the protected environment.
Horticultural glass
Good light transmission over long period.
Reasonable heat retention.
Long lasting.
Heavy, difficult to handle and cut and will not bend.
Polythene sheeting
Cheaper than glass.
Doesn’t last long, UV inhibitor will extend lifespan.
Doesn’t retain long wave radiation so it cools down quickly once sun has set.
When used to clad polythene tunnel condensation occurs.
Twin walled poly carbonate.
Very expensive.
Reasonable light transmission, deteriorates with time.
Excellent heat retention.
Large sheets can be used and it is easily cut.
Acrylic sheets
Rigid plastic sheets.
Good light transmission.
Can be mounded into shapes e.g. Curves, can be drilled, doesn’t shatter.
Lighter than glass but stronger when hit.
Can transmit UV light or filter it out.
Maximising light levels in a new greenhouse.
Include high eaves and angled roof in design.
Avoid shady site.
Optimum orientation - E/W for maximum light transmission.
Use aluminium/steel framework for low structure to glass ratio.
Manipulation of light levels within a growing structure.
Supplementary lighting - artificial lights suspended from above crop, activated according to day length and amount of natural light.
Shading - application of shading to the exterior of protected structure eg. Shade paint or blinds, during summer months.
Can be erected inside structure, eg. Rokolene to cut out damaging effects of direct sunlight e.g. Leaf scorch
Selecting containers for indoor plant display.
Management considerations.
Type of plants are going to be planted?
Container must be watertight.
Weight of container when full of growing media.
Life-span of container.
Suitability of container for specific watering system e.g.hydroculture.
