PROTECTED PLANT PRODUCTION

Learn Greenhouse and shade house growing of different crops; choosing and using different structures and equipment for controlling growing environment and conditions.

Course Code: BHT223
Fee Code: S2
Duration (approx) Duration (approx) 100 hours
Qualification
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Learn how to grow plants in a greenhouse
or other protected situation, such as a shade house. 
  • for large or small scale growing, established or new operations
  • improve your understanding of how plant growth can be controlled
  • explore business and career opportunities; improve your value as an employee, improve your profitability as a flower grower, market gardener or nurseryman.

 

You can grow all sorts of plants in a greenhouse, and achieve all types of things, which you might not be able to achieve otherwise, whether growing as a hobby or commercially. 
 

Lesson Structure

There are 10 lessons in this course:

  1. Structures for Protected Cropping
    • Introduction
    • The greenhouse business
    • The greenhouse system
    • Components of a greenhouse facility
    • Deciding what you need
    • Siting a greenhouse
    • Suitability of different structures for specific cropping, depending on natural light transmission
    • Cleanliness in a greenhouse
    • Types of greenhouses
    • Construction method
    • Framing materials
    • Covering materials
    • Benches or beds
    • Flooring
    • Guttering
    • Doors
    • Ventilators
    • Common designs - venlo, wide span, multi span, mansard, polytunnel, saw tooth, single span, retractable roof
    • Relationship between shape and light transmission
    • Shade houses
    • Conservatories
    • Shade house design
    • Cold frames
  2. Environmental Control
    • Introduction
    • Control of Environment
    • Measuring Environmental factors -natural light, growing media temperature. air temperature
    • Misting
    • Fog
    • Problems in Greenhouses
    • Heating and ventilation systems
    • Thermal screens
    • Insulation
    • Lighting equipment
    • Artificial light
    • Photosynthesis
    • Calvin Cycle Plants
    • Krantz Cycle Plants
    • Day length manipulation
    • Long day length plants
    • Short day length plants
    • Day length neutral plants
    • Heated propagators
    • Irrigation and nutrition control
    • Optimum temperature, humidity and light for selected plants
  3. Cladding Materials and their properties
    • Factors affecting light transmission - shape and orientation
    • Covering materials
    • Coreflute/Polyflute
    • PVC
    • Polycarbonate
    • Fibreglass
    • PVC Film
    • Reinforced PVC Film
    • Heat Insulation and Cost Effectiveness
    • Windbreaks
    • Light transmission properties
  4. Irrigation
    • Nursery Irrigation
    • Irrigation Practices
    • Irrigation syustems
    • Plant water needs, excess and deficiency
    • Automatic irrigation systems
    • Sprinkler types
    • Overheads watering
    • Flood benches
    • Capillary watering
    • Trickle irrigation
    • Pulse watering
    • Seep hoses
    • Watering cans
    • Water supply and quality
    • Liquid feed systems
    • Water treatment
    • Water sources
    • Scheduling irrigation
    • Water system maintenance
  5. Nursery Nutrition and Soil Characteristics
    • Fertilisers in greenhouses
    • Diagnosing Nutritional problems
    • Nutrition management
    • Soils, media and nutrition
    • Pore space in soils and growing media
    • Percolation rates
    • Buffering capacity
    • Cation exchange capacity
    • Soil temperature
    • Soil pH
    • Laboratory testing
    • Soil sampling
    • Measuring pH and salinity
    • Fertiliser types
    • Applying fertilisers
    • Fertiliser problems
    • Applying liquid fertilisers
  6. Relationship between Production techniques and Horticultural practices
    • What crops are grown under cover
    • Potting media
    • Potting mix components
    • Potting mix problems
    • Water repellency
    • U.C. Mixes
    • Knoxfield research
    • Potting mix standards
    • Propagation media
    • Pots and containers
    • Potting up plants
    • Transplanting between pots
    • Perched water tables
    • Production of different crops
    • Tomato production
    • Lettuce production
    • Potted begonias
    • Carnations
    • Greenhouse roses
    • Hydroponics
    • Propagation methods -overview
    • Plant hormones
    • Planting and crop establishment
  7. Greenhouse Management: Pests and diseases
    • Fungi
    • Common fungal problems
    • Chemical and cultural control of disorders
    • Legislation & labels
    • Biological and integrated pest management
    • Beneficial agents
    • Economic thresholds
    • How pest and disease may be introduced to a greenhouse
    • Identifying major problems -viruses, bacteria, fungi, nematodes
    • Pests
    • How to determine the problem
    • Conducting an inspection
  8. Harvest and Post Harvest Technology
    • Stage of growth for harvesting
    • Shelf life
    • Post harvest treatments
    • Grading
    • Cut flowers
    • Conditioning for market
    • Marketing at a wholesale market
    • Culture & management requirements for selected greenhouse crops
    • Harvest & post harvest for different orchids
    • Transport and storage of flowers
    • Post harvest requirements of mushrooms
    • Grading systems
    • Mechanised grading
    • Fruit grading
  9. Greenhouse Plants
    • What is suited to growing in a greenhouse
    • Growing specific crops
    • Growing lilies in a greenhouse
    • Growing roses in a greenhouse
    • Growing tomatoes in a greenhouse
  10. Risk Assessment
    • Identifying risk in a workplace
    • Safe work practices with clothing and equipment
    • Workplace policy
    • Identifying hazards
    • Risk control methods
    • Risk assessment for protected crop production
    • Manual lifting
    • How to lift safely
    • Using machines for heavy work -including cultivation
    • Cleaning and sharpening tools

Aims

  • Describe and evaluate types and shapes of modern growing structures
  • Describe and evaluate environmental controls in protected cropping
  • Explain the nature of solar radiation, transmission properties of glass and other materials used to cover greenhouses
  • Determine the water requirements of a greenhouse grown crop; including appropriate methods of irrigation
  • Relate horticultural principles to the production and harvesting of a range of greenhouse grown crops
  • Evaluate factors that affect successful marketing protected crops
  • Undertake risk assessment for plants growing in a greenhouse

What You Will Do

  • Identify the main types of growing structure
  • Relate use of structures to shape and type of construction
  • Identify the range of environmental factors controlled within a growing structure
  • Describe the use of the equipment used to measure and monitor these factors
  • Name and describe a range of types of environmental controls
  • Evaluate the use of IT facilities for environmental control
  • Describe the meaning of “daylight” and explain the role of sunlight and diffused light
  • Relate time of year to the quantity and quality of available light
  • Evaluate how the shape and orientation of a structure will affect light transmission
  • Assess the effectiveness of glass and cladding alternatives for light transmission
  • Describe the durability and insulation properties of glass and alternative materials
  • Select and describe appropriate systems of irrigation for plants grown in situ
  • Select and describe appropriate systems of irrigation for container grown plants
  • Specify and evaluate systems for incorporating plant nutrients into the irrigation water
  • Explain the effects of environmental control on a range of plants
  • Relate the essential features necessary for successful plant establishment and development to their underlying scientific principles.
  • Describe the production of a range of crops
  • State the optimum stage of growth for harvesting a range of crops
  • Describe the harvesting systems for protected crops
  • Explain how shelf life can be affected by pre and post harvesting treatment of the crop
  • State the factors to be considered when marketing crops
  • Evaluate alternative marketing outlets
  • Relate packaging & presentation to marketing
  • Assess benefits to the grower and customer, of grading a crop before marketing
  • Determine elements of risk in the practical operations associated with protected plant production.
  • Identify safe working practices in a greenhouse or shadehouse.

How to Cause Crops to Flower or Fruit Out of Season
 
Flowering occurs when there is a sudden change in the growing point, from vegetative organs (i.e.: leaves, stems, leaf buds) to floral organs. When this happens, the apical dominance (i.e. the dominance of the growth in the upper end of stems that inhibits growth of lateral buds) usually weakens.

The initial stimulus to cause this change in tissue type appears to normally originate in the leaves (though not always). Some target cells or tissues are stimulated by a fairly non specific trigger, setting off a chain reaction (cascade) throughout the involved tissue. Much work has been done trying to discover the chemistry of these changes, but the results tend to only show that there is a very great complexity involved.

As flowering tends to be related to particular times of the year, the initial stimulus is most obviously environmental. There are three possible types of environmental stimuli:
  • Physical eg: Changes in photoperiod (longer/shorter days), humidity, pressure
  • Electrical e.g: Changes in pH
  • Chemical: Changes in levels of certain chemicals eg: More light increases photosynthesis, which increases levels of sugar in the plant

There are two types of chemicals involved both promoters and inhibitors. The promoters stimulate the process of flower induction. The inhibitors inhibit this inductive process. The promoters & inhibitors do not work together in a balancing interaction. They affect each other through an interference process.
(eg: With Kalanchoe, short days produce promoters, but if more than one third of the days are long, sufficient inhibitors are produced to stop the affect of the promoters).

JUVENILITY is a completely different thing to the effect of inhibitors. A plant cannot respond to the affect of flowering promoters until tissue has gone through a phase change to reach maturity. It is possible for this phase change to be reversed and mature tissue become juvenile again.

Types of flowering response to temperature
Temperature can affect time of flowering from sowing, three different ways:
  1. Vernalization where cold temperature hastens flowering.
  2. Rate of flowering process increases over a sequence of different temperatures. The final stage is an optimum temperature where flowering is most rapid.
  3. Supra Optimal Temperatures Stressful temperatures which delay flowering as temperatures become warmer.

Ways to cause controlled flowering

  • If the plant suffers juvenility problems, then propagation can be done vegetatively eg: Boronias will only flower if the plant is a mature established one. A Boronia raised from seed will not flower for some time, but if a plant is grown from a cutting off an established plant it will flower sooner.
  • Photo period: changes in exposure to sun light will trigger flowering in some species
  • Type of light (eg: red light on short day or long day plants)
  • Temperature
  • Gas eg: Carbon Dioxide enrichment on short day plants. Lack of carbon dioxide availability to leaves stops flowering production.


Principles affecting rates and progress of flowering
 
A. Rates and progress toward flowering, virtually always, bears a linear relationship to either photo period or temperature or both. eg: As temperature increases, flowering increases or progresses towards development. The more temperature, the more flowering. Or as temperature decreases, flowering increases or as light increases, flowering decreases, etc.
 
B. The basic temperature response (not affected by photo period) is applicable to almost all annual crops.
 
C. A photoperiod temperature response is common to all photo period sensitive plants. Photo period sensitivity varies among species & cultivars. The greatest sensitivity is with tropical (short day) plants where differences between day lengths are very small. In this case the response is to mean temperature usually.
 
D. Environment insensitive plants generally have no response to either mean temperature or photo period.
 
E. Where temperatures are excessively above optimum levels there is a negative, lineal relationship, between mean temperature and flowering. Most generalizations refer to non stress temperatures.
 
F. Variable daily contributions by photo period and temperature conditions can be treated as additive increments towards flowering.


Applied flowering control
  • There have been a few cases where treatment with auxin (hormone) or ethylene generating substances has induced flowering (eg: Bromeliaceae)
  • There is more likelihood in the near future to finding chemical inhibitors to flowering rather than chemical stimulants. Inhibitors would be useful to stop pasture grasses from flowering, for instances.
 



Course Contributors

The following academics were involved in the development and/or updating of this course.

John Mason (Horticulturist)

Parks Manager, Nurseryman, Landscape Designer, Garden Writer and Consultant.
Over 40 years experience; working in Victoria, Queensland and the UK.
He is one of the most widely published garden writers in the world; author of more than 70 books and edito

Yvonne Sharpe

RHS Cert.Hort, Dip.Hort, M.Hort, Cert.Ed., Dip.Mgt. Over 30 years experience in business, education, management and horticulture. Former department head at a UK government vocational college. Yvonne has traveled widely within and beyond Europe, and has

Dr. Lynette Morgan (Crops)

Lyn has a broad expertise in horticulture and crop production. Her first job was on a mushroom farm, and at university she undertook a major project studying tomatoes. She has studied nursery production and written books on hydroponic production of herbs.

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