2. Structural Parts

3. Greenhouse Types
Even Span: Self-supporting commercial greenhouse and is the most common type of greenhouse
Ridge-and-furrow: Two or more even-span greenhouses connected together at the eaves
Contiguous: Two or more even-span greenhouses with inner walls separating each greenhouse

4. Greenhouse Types
Quonset: Upside down half circle made of laminated wood or bent pipe. Can also have raised walls
Gothic: Slightly pointed greenhouse covered with corrugated fiberglass. Provides greater load bearing for accumulation of snow
Lean-to: Seldom used commercially and found attached to the south wall of a south supporting structure

5. Greenhouse Frame When building a greenhouse frame consider:
The strength and weight of the materials
The amount of shade cast by the frame
The frame is composed of:
Perlins
Sash bars
Side posts

6. Framing Materials Aluminum Plastic pipe Wood or wood combination
Alloy: Aluminum combined with other materials to increase strength and flexibility with rust and rot resistance
Plastic pipe
Wood or wood combination

7. Covering Materials Glass Plastic, flexible Plastic, rigid Cover Type
Advantage
Disadvantage
Glass
Best for transmitting light to plants
Initially expensive
Easily broken
Plastic, flexible
Provides insulation
Inexpensive
Pass less light to plants
Considered temporary
Often need replacement after one or two years
Plastic, rigid
Last longer that flexible plastic
Less chance of breaking
Withstand weather better than flexible plastic
Will eventually yellow or weaken
Pass less light than glass

8. Heating Systems Unit heaters Hot water heat Root zone heaters
Steam heat
Infra-red heating
Solar heating

9. Cooling Systems Evaporative cooling Natural cooling Fog cooling
Pad absorbs water and exhaust fans pull air through the pad and greenhouse
Natural cooling
Replaces air inside greenhouse with outside air
Fog cooling
Fog nozzles installed in greenhouse emit a fog

10. Benches and Beds
Raised benches: raised off the floor, generally inches
Ground beds: constructed directly on the floor and filled with media
Movable benches: also called rolling benches, raised bench built to roll sideways
Ebb and flow bench: raised bench approximately 3-6 inches deep and capable of holding water

11. Common Bench Arrangements
Parallel: Benches run the length of the greenhouse and have several aisles
Peninsular: One major aisle in the center or the greenhouse with short perpendicular aisles