Greenhouse Structural Components Greenhouse Management

Structural Components Greenhouses are made by assembling different parts or components. Each part has a specific role in the overall greenhouse structure.

This slide shows the basic components of a greenhouse

Side Posts Support the trusses and bear the weight of the greenhouse. Set in concrete footings. Typically spaced 10 feet apart.

Curtain Wall The first several feet of sidewall above the soil line. Usually made of some solid building material such as poured concrete, concrete blocks, bricks, or treated lumber.

Sill The top of the curtain wall

Eave Where the sides of the greenhouse join the roof of the greenhouse. The “top” of the sides of the greenhouse.

Truss Structural component that supports the weight of the greenhouse roof. Consists of rafters, struts, and chords.

Purlin Purlins run the length of the greenhouse. Keep the roof trusses aligned.

Ridge Where the roofs come together at the top of the greenhouse. Many greenhouses have a ridge vent(s).

Sash Bars Run perpendicular to the purlins. Attached to the purlins. Hold the glazing in place. Sometimes built with a drip groove or channel to catch condensation that forms on the inside of the glass panels. sash bars

Wooden Sash Bar Close-up Sash bar cap Glass panels Sash bar Drip groove

Aluminum Sash Bar Close-up

Sash Bar Cap Fastened to the sash bars with screws. Functions to hold the glass panels in place.

Siting a Greenhouse Topography Amount of land Select as level a site as possible. Amount of land The general “rule of thumb” is to purchase at least twice as much land as the desired growing area. For example, you desire to build a ridge & furrow greenhouse measuring 50 feet x 150 feet. 7,500 square feet x 2 = 15,000 square feet = .34 acres

Greenhouse Orientation W E S N Depends on latitude and whether the greenhouse is connected or detached. Single, detached greenhouse: In northern latitudes an east-west orientation is favored because light can enter through the sides rather than through the ends of the greenhouse where it would cast more shade. Also, because our winds are predominately from the west (blue arrow) this positions an end wall of the greenhouse into the wind.

Greenhouse Orientation Connected Greenhouses: An east – west orientation is not ideal. North South

Greenhouse Orientation Connected Greenhouses: A north – south orientation is BEST! South North

Windbreaks Planted on the north and west sides of the greenhouse. Help reduce heat loss from the greenhouse. Greenhouses should be located a minimum of 100 feet away.

Framing Materials Two basic kinds of material: Wood Metal; primarily aluminum or aluminum alloys

Wood Redwood, cedar, or some other rot-resistant wood. Treated wood. Beware of mercury-based paints and preservatives because fumes from these products are toxic to plants.

Aluminum Lightweight Strong Rust resistant Framing materials can be manufactured thinner and be spaced further apart allowing for minimal shading.

Stresses on the Greenhouse Weight of the framing and glazing. Snow loads. Wind pressure. Temperature; fluctuating temperatures cause expansion and contraction of framing and glazing materials.

Headhouse Service building with overhead doors. Used for planting, media preparation and storage, chemical storage, container storage and office space, etc.

Headhouse, continued… May also include the heating plant (boiler) and a cold storage facility. Should be at least 10% of the total growing area of the greenhouse.

The End