greenhouse structures and systems ert 352. a greenhouse is an area designed to grow plants. it is a...

Greenhouse Structures and Systems

ERT 352

• 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.

What is a greenhouse?

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– 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

uneven-span

even-span

ridge-and-furrow

Single Span Greenhouse

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

• 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

1. GLASS

• ADVANTAGES:– 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:– FIBERGLASS– ACRYLIC- PLEXIGLASS – POLYCARBONATE- LEXAN

• ADVANTAGES:– Light weight– Most Durable

• DISADVANTAGES:– More expensive than flexible plastic

Cooling and Ventilation Systems

1. No Cooling

2. NATURAL VENTILATION

3. FAN & SHUTTER COOLING

4. FAN & SHUTTER COOLING with SHADE CLOTH

5. Evaporative Cooling

6. 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)

• Pad

• Water Tank With pump

D. IRRIGATION

1. Drip irrigation

2. Mist nozzles

3. Fertilizer injectors

4. Automatic Controls

5. 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

Greenhouse Structural Components

Greenhouse Structural Components

Greenhouse Structural Components

Greenhouse Structural Components

Greenhouse Structural Components

Ridge-and-Furrow Greenhouses

Other structural components

Wooden framing.

Sawtooth Construction