Greenhouse Cut Flowers

Course CodeVHT239
Fee CodeS3
Duration (approx)100 hours
QualificationStatement of Attainment

Greenhouse Cut Flower Production is intensive horticulture. It requires less land but a greater investment inequipment (compared with production in the open). This form of proddiction can also be more complex -requiring not only an understanding of the plants and related horticultural skills; but also an understanding of how to provide and manage artificial environments.

This course is unique and ideal training for anyone looking to work in this exciting and rewarding field of horticulture.

Lesson Structure

There are 12 lessons in this course:

  1. Introduction to Cut Flower Production
    • Nature and scope of Cut Flower production
    • Flower Characteristics
    • What can you grow
    • Flower (botanical) structure
    • Hydroponics
    • Soils for Flower Growing
    • Soil pH, Cation Exchange Capacity, Conductivity
  2. Cultural Practices
    • Planting procedure
    • Time of planting
    • Flowering Plant Nutrition
    • Watering
    • PruningStaking
    • Mulching
    • Environmental Protection
    • Factors affecting growth
    • Soil Testing
  3. Flower Initiation and Development
    • Getting plants to flower out of season
    • Principles affecting rates and progress of flowering
    • Case Studies -Narcissus, Azaleas
    • Carbon Dioxide Enrichment
  4. Pest & Disease Control
    • Managing problems in a greenhouse
    • Fungi
    • Pests
    • Media Sterilisation
    • Pest and Disease Control Measures
  5. Greenhouse Management A.
    • Greenhouse types
    • Fibreglass, glass, coreflute, film etc
    • Hotbeds
    • Cold Frames
    • Shade Houses
    • Misting Systems
    • Lights
    • Benches and Beds
    • Environmental Controls
  6. Greenhouse Management B.
    • Optimum Growth for Different Plants
    • Temperature control methods
    • Heat Loss
    • Heaters
    • Greenhouse irrigation
    • Cooling
  7. Management, Harvest and Post Harvest
    • General rules for harvesting flowers
    • What flowers last longest
    • Customer requirements
    • Post harvest handling
    • Post harvest treatments
    • Managing a market garden
    • Crop scheduling
    • Standards
    • Production costs and prifit
    • Farm layout
  8. Herbaceous Perennials
    • Perennials
    • Carnations
    • Chrysanthemums
    • Gerbera
    • Judging Flowers
  9. Annuals & Biennials
    • Antirrhinum
    • Aster
    • Stock
    • Centaurea
    • Delphinium
    • Limonium
    • Zinnia
  10. Bulbs, Corms, Tubers & Rhizomes
    • Alstroemeria
    • Amaryllis
    • Dahlia
    • Freesia
    • Gladiolus
    • Iris
    • Lilium
    • Tulip
  11. Filler Plants
    • What is a filler
    • Gypsophila
    • Ferns
    • Heliconias
    • Calathea
  12. Miscellaneous Greenhouse Cut Flowers
    • Roses
    • Orchids

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.

Aims

  • Describe the nature and scope for greenhouse flower production.
    • Explain cultural practices commonly needed for developing and maintaining good growth in a flower crop.
    • Explain initiation and development flowers.
    • Determine management practices greenhouse flower growing.
    • Discuss greenhouse management techniques for cut flower production.
    • Explain greenhouse management techniques for flower production.
    • Describe harvesting of flowers
    • Describe post harvest of cut flowers.
    • Determine greenhouse production techniques different flower crops, including: selected herbaceous perennials, annuals, biennials, bulbs, corms, rhizomes or tubers, filler plants, roses and orchids.

How to Harvest Cut Flowers
 
Stage of Growth
Bud Harvesting is a procedure whereby flowers are harvested and transported at bud stage. The wholesaler then stores the buds or allows them to open for resale. Once open, the flower has at least the same length of shelf life as a mature harvested flower. The advantages of early harvest include the grower is able to produce more crops per year in the same amount of space and as they are closed buds, they are more immune to injuries from handling.

Shelf Life
A fresh cut flower is still a living specimen even though it has been cut from the plant. The maximum vase life is short. As much as 20% of harvested flowers become unmarketable as they move through the marketing process (harvesting, packaging, transporting and selling). A significant proportion of the remainder are sold in a weakened state.

The practices that improve crop quality before harvest also continue to improve the shelf life. A crop grown with poor light intensity will be low in carbohydrate content. Respiration continues after the flowers are harvested, but little photosynthesis occurs as light is limited in the packinghouse, florist shop and purchaser’s home. When carbohydrates are low, respiration is low and flower deterioration occurs rapidly. Therefore optimum light intensity is important and relative to vase life. Even the time of day when the flowers are cut can have an impact of longevity. Carbohydrates build up during the day through photosynthesis and reach a peak late afternoon. Flowers cut late afternoon were found to last longer than those cut early morning.

Temperature also has an effect on shelf life, because it influences photosynthesis and respiration, which in turn affects carbohydrate accumulation. If temperatures are raised in the greenhouse to force earlier flowering the vase life is shortened.

Nutrition of the crop has an effect on shelf life as well. Under or over supply of nutrients including nitrogen, calcium, magnesium iron and manganese that reduce photosynthesis will reduce shelf life. 

The main reasons fresh flowers deteriorating include:

  • Inability of the stems to absorb water because of stem blockage
  • Excessive water loss from the cut flower
  • A limited supply of carbohydrate to support respiration
  • Diseases

Premature wilting is caused by the xylem (water conducting tubes in the stem) being blocked by bacteria, yeast or fungi living in the water or on the flower foliage. These microorganisms rapidly multiply and their chemical components plug the stem ends, restricting water absorption.

Excessive water loss from flowers after harvest can lead to reduced shelf life. Immediately, after harvest, flowers should be refrigerated. Flowers need to be in water or in cool conditions as much as possible from the time they are cut.
Low carbohydrate supply usually occurs as a result of improper storage temperature and handling. Low temperatures reduce respiration and conserve carbohydrate reserves thereby prolonging quality and shelf life.

Post-Harvest Treatments
There has been a great deal of research conducted to find methods for prolonging the life of cut flowers. Floral preservatives perform three main functions:

1. They provide sugar (carbohydrate).
2. They provide a bactericide to prevent microbial growth.
3. They acidify the solution. This suppresses bacterial development and prevents wilting of flowers.

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