Structural Parts

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

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

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

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

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

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

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

Benches and Beds Raised benches: raised off the floor, generally 24-36 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

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