Greenhouse Structures

1. Greenhouse Structures Original by Mark Morgan Berrien County High School Edited by Georgia Agriculture Education Curriculum Office July 2002

3. Different Types of Attached Greenhouses: • A. Lean-to • B. Attached even-span • C. Window mounted

4. Free standing greenhouses: • A. Even-span • B. Uneven-span • C. Gothic arch • D. Quonset

5. Connected greenhouses: • A. Gutter connected • B. Ridge-and-furrow

6. Materials used to frame a growing structure • A. Wood • B. Metal

7. Advantages and disadvantages of framing materials • Wood-Very good for hobby greenhouses or small custom designed houses: has a low initial cost but requires large amounts of maintenance and painting. • NOTE: The use of pressure treated chromated copper arsenate lumber is recommended. Never use wood treated with creosote or penta chloro-phenal; it releases toxic fumes.

8. Advantages and disadvantages of framing materials. • Galvanized metal-Most commonly used structural material. Due to a coating on the material, very little maintenance is needed and the frames are strong and long lasting. • The cost is higher initially but is cheaper in the long run. Most greenhouse kits come with galvanized metal frames that are predrilled and ready for assembly.

9. Identify the types and their characteristics of greenhouse coverings: • A.Glass • B. Rigid plastic: fiberglass and poly- carbonate/acrylic • C. Flexible polyethylene

10. Advantages and disadvantages of each covering. • Poly-carbonate-A rigid greenhouse covering that is made of double layers, has high light transmission, is flame retardant and has the strongest resistance to breakage. • NOTE: This material may be bent, cut, drilled or nailed and does not require special installation.

11. Polyethylene-A flexible film that is used as a greenhouse covering. • NOTE: Polyethylene, often called poly, is the most common greenhouse covering material due to the low initial cost. It is expensive over the long term due to frequent replacement. It is easy to apply, has excellent heat retention, has little resistance to force, is flammable and is degraded by ultraviolet light

12. Fiberglass-A semi-rigid covering material made by embedding strands of fiber in a plastic resin. • NOTE: These sheets of greenhouse covering material may be flat or corrugated, are very durable and may be bent, cut, or nailed. Probably the least expensive greenhouse covering in the long run. Fiberglass is flammable.

13. Glass-A greenhouse covering that has the highest light transmission; comes in rigid panels that are especially made for greenhouses; has the longest life expectancy and high maintenance requirements. • NOTE: It is seldom used today because of cost.

15. What is a headhouse? • A. Service building of a greenhouse • B. Used for storage • C. Planting area • D. Mixing soil • E. Cold storage • F. Loading docks • G. Office • H. Worker break area

16. Where should a headhouse be located? • A. Center of greenhouse range • B. North end/side of greenhouse • C. Can help as a windbreak • D. Reduce heat loss

17. Students will design a greenhouse operation that includes the following: • 1. Location and its size and zoning requirements • 2. Address the requirements for site location in Lesson 1 • 3. Identify: • Kind of structure • Type of framing material • Type of covering • Include plans for a headhouse.

18. The entire structure is 16' x 20'. A wall down the middle will separate the greenhouse half from the storage shed half (each 8' x 20').The subfloor is made entirely of treated lumber, 2" x 8". There are nine 4x4 posts cemented in the ground for support. The joist for the shed half are spaced closer together to bear the load of the power equipment to be stored there.

19. From the other angle, the rigid foam (foil faced) insulation for the greenhouse floor is visable. The inside floor-joists on the greenhouse side are lowered 1/2" to allow for the insulation thickness. This way the floor sheeting (treated plywood) layed flat across the entire joist structure. The small opening is an access hatch for the utilities.

20. This is a close-up of the GH trusses. Glazing panels will be installed into the openings on the left. The trusses are treated lumber and a jig was made to fabricate these. You can see the plywood gusset's on each side of the trusses, which were glued and firmly nailed for strength.

21. The double walled glazing panels (twin walled polycarbonate sheets) have been installed in the roof and the knee wall. The end walls are being finished; the roof has been shingled. Metal flashing was used to ease the sealing of where the roof and short wall met.

22. The exterior sheeting is installed. The three doorways are visible from the extreme left, a sliding 'barn type' door, then a 6' x 6' garage door for the shed, and the doorway for the greenhouse.

23. We insulated all greenhouse walls. The center dividing, ends, and the ceiling. The ceiling drywall is the water resistant type, an overkill but we decided to play it safe.

24. Tim built a nice potting bench with a removable tray. It was final coated with polyurethane. Underneath is a small shelf, and a container for the potting soil. The lone window gives a view while working. Above you can see the temperature controlled exhaust fan. The interior walls are pine siding treated with a water sealer . The treated plywood floor was sealed as well; again playing it safe!

25. Finished and ready for plants. The bench frame is treated lumber topped with expanded metal greenhouse mesh which allows plenty of air circulation around the plants. The water spigots and propane heater were installed later. Below is the completed outside view

27. The End