Greenhouse Structures
What does your house provide you with? What are the important features of a home that provide these things? What should a greenhouse provide plants? What features could provide these things?
Student Learning Objectives 1. Identify greenhouse designs. 2. Identify considerations for greenhouse frameworks. 3. Identify and describe greenhouse glazing materials.
Objectives Cont. 4. Describe the functions of the headhouse. 5. Discuss the advantages of retractable-roof greenhouses. 6. Describe greenhouse bench options.
Terms Acrylic structured sheets Bench Even-span greenhouse Fiberglass Glazing Greenhouse
Terms Greenhouse framework Headhouse Hoop-house Lean-to greenhouse Polycarbonate structured sheets Polyethylene Retractable-roof greenhouse
Terms Ridge-and-furrow greenhouse Rolling bench Structured sheets Uneven-span greenhouse
What are the common greenhouse types? A greenhouse is a structure enclosed by glass or plastic that allows light transmission for the growth of plants. There are four basic styles of greenhouse design. The lean-to greenhouse shares a wall with a building and relies on the building structure to provide support for the roof.
Lean-to Greenhouse Courtesy, Interstate Publishers, Inc.
Even-span greenhouse structures are single houses that have roofs with an even pitch and an even width. A common even-span greenhouse that uses arching pipes for the framework is called a hoop house.
Even Span Greenhouse Hoop house
Uneven-span greenhouses have unequal pitches and widths Uneven-span greenhouses have unequal pitches and widths. Use of this style is limited to hillsides. Ridge-and-furrow greenhouse structures consist of a number of greenhouses connected along the length of the house.
Uneven Span Greenhouse Ridge and Furrow Greenhouse
Create a Greenhouse Use the marshmallows and toothpicks to create a greenhouse of one of the styles we have just discussed.
What considerations need to be addressed for greenhouse frameworks? The greenhouse framework supports the greenhouse covering material. The framework should be strong, yet allow the maximum amount of light to reach the plants.
Aluminum and aluminum/steel Wood Angle iron Plastics long lasting, low maintenance Wood Not used much anymore Angle iron Ornate but heavy Plastics Cheap but light and easily broken
What materials are used for greenhouse glazing? The covering of the greenhouse is referred to as the glazing. Considerations include: Durability Light transmission Cost Heating costs Start Here
Flexible sheets of polyethylene are stretched over the greenhouse framework. Structured sheets, including polycarbonate, acrylic, and fiberglass, which are made with double walls offer good insulation.
Polyethylene Good insulator Cheap Flexible Lasts 5-7 years
Polycarbonate structured sheets Most widely used Good light transmission Resist hail damage Easy to work with.
Polycarbonate sheets Box shaped tubes
Acrylic structured sheets High light transmission Cost more than polycarbonate sheets Prone to hail damage Less flexible than polycarbonate
Solid plastic sheets
Fiberglass Dropped in popularity Discolors after 7-10 years Flammable Poor insulator
Glass Best material for crop production Highest light transmission Long lasting Expensive Breakable
What are the functions of the headhouse? Storage area Potting area Office Shipping area Headhouse Supports the production of greenhouse crops Attached to greenhouse
What are the advantages of retractable-roof greenhouses? Allow the roof to be opened and closed.
Open the roof when weather conditions are favorable Close the roof when crops need protection
Provide plants with increased light levels and fresh air Prepare outdoor crops for elements before leaving the greenhouse Reduced disease problems Better ventilation Reduced irrigation Rainfall More effective temperature control for DIF.
What are greenhouse bench options? Structure that holds the plants above the ground. Arranged with aisle space and growing space in mind Made of expanded galvanized steel Aluminum Plastic Rot resistant wood
Rolling benches maximize growing space by limiting space for aisles Rolling benches maximize growing space by limiting space for aisles. The benches are placed on pipes, which allows them to be easily moved from side to side.
Bench layouts conventional Peninsular Movable benches
Review/Summary What are the common greenhouse sizes? What considerations need to be addressed for greenhouse frameworks? What materials are used for greenhouse glazing?
Review/Summary cont. What are the functions of the headhouse? What are the advantages of retractable-roof greenhouses? What are greenhouse bench options?