1. Greenhouse Structures

2. 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?

3. Student Learning Objectives
1. Identify greenhouse designs.
2. Identify considerations for greenhouse frameworks.
3. Identify and describe greenhouse glazing materials.

4. Objectives Cont. 4. Describe the functions of the headhouse.
5. Discuss the advantages of retractable-roof greenhouses.
6. Describe greenhouse bench options.

5. Terms Acrylic structured sheets Bench Even-span greenhouse Fiberglass
Glazing
Greenhouse

6. Terms Greenhouse framework Headhouse Hoop-house Lean-to greenhouse
Polycarbonate structured sheets
Polyethylene
Retractable-roof greenhouse

7. Terms Ridge-and-furrow greenhouse Rolling bench Structured sheets
Uneven-span greenhouse

8. 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.

9. Lean-to Greenhouse
Courtesy, Interstate Publishers, Inc.

10. 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.

11. Even Span Greenhouse
Hoop house

12. 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.

13. Uneven Span Greenhouse
Ridge and Furrow Greenhouse

14. Create a Greenhouse
Use the marshmallows and toothpicks to create a greenhouse of one of the styles we have just discussed.

15. 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.

16. 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

17. 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
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18. 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.

19. Polyethylene
Good insulator
Cheap
Flexible
Lasts 5-7 years

20. Polycarbonate structured sheets
Most widely used
Good light transmission
Resist hail damage
Easy to work with.

21. Polycarbonate sheets
Box shaped tubes

22. Acrylic structured sheets
High light transmission
Cost more than polycarbonate sheets
Prone to hail damage
Less flexible than polycarbonate

23. Solid plastic sheets

24. Fiberglass Dropped in popularity Discolors after 7-10 years Flammable
Poor insulator

25. Glass Best material for crop production Highest light transmission
Long lasting
Expensive
Breakable

26. What are the functions of the headhouse?
Storage area
Potting area
Office
Shipping area
Headhouse
Supports the production of greenhouse crops
Attached to greenhouse

27. What are the advantages of retractable-roof greenhouses?
Allow the roof to be opened and closed.

28. Open the roof when weather conditions are favorable
Close the roof when crops need protection

29. 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.

30. 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

32. 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.

33. Bench layouts
conventional
Peninsular
Movable benches

34. Review/Summary What are the common greenhouse sizes?
What considerations need to be addressed for greenhouse frameworks?
What materials are used for greenhouse glazing?

35. Review/Summary cont. What are the functions of the headhouse?
What are the advantages of retractable-roof greenhouses?
What are greenhouse bench options?