Greenhouse Structures and Systems ERT 352

What is a greenhouse? A greenhouse is an area designed to grow plants. It is a controlled environment which allow optimum growth. When several of these buildings are joined together they are often referred to as a greenhouse range. A greenhouse at home is usually attached to the house or the garage.

Location There are several factors to be considered in establishing a greenhouse range. A. Room for expansion 1. Land larger then immediate needs should be acquired. 2.Area should be added to this figure to accommodate service buildings, storage, and access drivers.

B. Topography 1. The building site should be as level as possible to reduce the cost of grading. 2. The site should be also well drained. Due to the vast amount of water in the green house it is always advisable to provide a drainage system. Try to select a site with deep, well drained loam, or sandy loam soil.

3. You should select a site with a natural wind break such as a tree line or a hill. C. Land use Prediction 1. Local zoning and tax laws are subject to change brought on by development pressures. Such changes have brought about the termination of many greenhouse business.

D. Climate E. Accessibility 1. The greenhouse site should be selected with specific crops in mind. E. Accessibility 1. A site should be selected which has easily accessible shipping routes. 2. Select a site that isn’t long distance. 3. Site location is often the deciding factor in the type of fuel used.

Types of Greenhouses Even Span Uneven Span Lean-to Quonset Gothic Arch Curvilinear Dome Shaped

lean to even-span uneven-span ridge-and-furrow

Single Span Greenhouse Note glazing materials. Double poly roof, poly carbonate endwalls.

1. EVEN SPAN Greenhouse with two roof slopes of equal pitch and width Benefits: Excellent light, ventilation, and temp control Disadvantages: Wasted heat air in the gables

EVEN SPAN

Even span gutter connected house.

2. GOTHIC ARCH Side walls are a short base wall of a solid material POINTED ARCH ROOF TRUSSES HAVE BEEN ELIMINATED Not as popular today Can have sidewalls Side walls are a short base wall of a solid material often cinderblocks

GOTHIC ARCH

3. QUONSET A greenhouse with a semicircular arch that starts at ground level or on top of a sidewall (Half moon shape) Benefits: Less Expensive to construct Few shadows Disadvantage: Cannot handle as much wind and snow

3. QUONSET

QUONSET

QUONSET WITH TOP VENT

4. RIDGE AND FURROW Several greenhouses connected along the length of the eaves Benefits: Large interior areas Reduced heat loss Less expensive construction Disadvantages: More difficult to control pest and temperature Difficult snow removal

RIDGE AND FURROW

RIDGE AND FURROW

RIDGE AND FURROW

RIDGE AND FURROW

RIDGE AND FURROW

Gutter connected house with automatic plant grader Gutter connected house with automatic plant grader. Klassic Beauties, Kerry's Bromeliad Nursery, Inc., Florida City, Florida

1. GLASS ADVANTAGES: DISADVANTAGES: Excellent Light Transmission Available DISADVANTAGES: Breakable High heat loss Most Expensive

2. FLEXIBLE PLASTIC FILMS EXAMPLES: PVC- POLYVINYL CHLORIDE PVF- POLYVINYL FLOURIDE FILM POLYETHYLENE- Most Common ADVANTAGES: Inexpensive Easy to Install DISADVANTAGES: Not as durable

3. RIGID PLASTIC SHEETS EXAMPLES: ADVANTAGES: DISADVANTAGES: FIBERGLASS ACRYLIC- PLEXIGLASS POLYCARBONATE- LEXAN ADVANTAGES: Light weight Most Durable DISADVANTAGES: More expensive than flexible plastic

Cooling and Ventilation Systems No Cooling NATURAL VENTILATION FAN & SHUTTER COOLING FAN & SHUTTER COOLING with SHADE CLOTH Evaporative Cooling Fan & Pad (Evaporative Cooling)

1. NO COOLING 1. Inside temperature of greenhouse can exceed 140 degrees F. 2. Plants will die within a short period of time.                                                                    

NATURAL VENTILATION

NATURAL VENTILATION

FAN & SHUTTER COOLING

FAN & SHUTTER COOLING

FAN & SHUTTER COOLING with SHADE CLOTH

Evaporative Cooling

EVAPORATIVE COOLING (Fan & Pad)

EVAPORATIVE COOLING (Fan & Pad) Water Tank With pump

D. IRRIGATION Drip irrigation Mist nozzles Fertilizer injectors Automatic Controls Solenoid valves

DRIP IRRIGATION (tubes)

MISTER (FOGGER)

FERTILIZER INJECTORS SLOWLY ADD FERTILIZERS TO IRRIGATION WATER, AT A SET RATE

IRRIGATION CONTROLS Solenoid Valves Help control flow rate

Greenhouse Structural Components Bottom Chord

Greenhouse Structural Components Struts and Chords Struts are under compression and chords are under tension stresses.

Greenhouse Structural Components A truss is made up of the side posts, rafter, struts, and chords. TRUSS

Greenhouse Structural Components Ridge

Greenhouse Structural Components Purlin

Greenhouse Structural Components Ridge Vent

Ridge-and-Furrow Greenhouses High Profile Low Profile The low profile greenhouse is also known as the venlo greenhouse. Cost differences between the two are very close and often negligible. Low profile greenhouses were originally designed to reduce the amount of surface area exposed to the cold and thus reducing heating costs. Why would you build a high profile greenhouse?

Other structural components rafter eave side post Mention sash bar sill curtain wall

Wooden framing.

Sawtooth Construction