Greenhouses

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Greenhouses

• Designed and Researched by
• 1999-00 Greenhouse and Turf Management Class
• John Koster, Paul Marsh, Jamie Wade, Nick Maneri
• Dan Dorfee, Jared Neid, Rob Stanley

Modified by Georgia Agricultural Education
Curriculum Office June 2002
Oakcrest High School, Mays Landing NJ
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Greenhouse

• Greenhouse location is very important, when
  placing your green house you must remember you
  will have to deliver your plant crops at all
  times of the year.
• Keep your greenhouse next to major roads to be
  sure that they are open through all times of the
  year to get goods to youre retailers

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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.

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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.

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• 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.

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• 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.

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• 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 isnt long distance.
• 3. Site location is often the deciding factor in
  the type of fuel used.

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Types of Greenhouses

• Even Span
• Uneven Span
• Lean-to
• Quonset
• Gothic Arch
• Curvilinear
• Dome Shaped

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Detached Greenhouses

• Detached Greenhouses - freestanding greenhouses
  that maybe constructed in one of several
  different styles.

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Even Span Greenhouses

• A detached greenhouse style that is most commonly
  used today for single houses or for several
  houses connected together to form one huge
  structure.
• Usually have clear spans with truss supports
  rather then supporting columns without the
  columns the heat closures can be used to conserve
  energy

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Uneven Span Greenhouses

• One side of the roof is longer than the other
  side
• When the longer side would face south, the suns
  heat could be used to maximum advantage
• High fuel costs are causing growers to switch
  back to this type of greenhouse

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Lean-to Greenhouses

• Built against other greenhouses or building
• The roof slopes to one direction usually facing
  south
• Small and may be added to other structures
• Used mostly for bulb-forcing or seed starting
  operations Lean-to-greenhouse is a half a
  greenhouse,split along the peak of the roof or
  ridge.
• This type of greenhouse is nice to have when
  space is a problem.

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Quon-set Greenhouses

• Used during World War II for storage sheds
• inexpensive and easy to buildFreestanding style
  is often a Quonset.
• Quonset is a arch shaped house, a bad thing about
  theses is the lack of height near the side walls.

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Gothic-arch Greenhouses

• Not widely used
• Framework formed from laminated wooden trusses
• The trusses are made up of a bunch of wood glued
  together
• Potted plants are usually grown in this type of
  greenhouse

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Curvilinear Greenhouses

• Used in city parks, botanical gardens, and
  wealthy individuals as conservatories
• Was used for large conservation.

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Dome shaped greenhouse

• Rarely used in the common flower greenhouse,
  because it is such a small greenhouse. But it is
  usually found in at technical institutes.

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Structure materials

• Galvanized steel rods make up the frame .
• The frame is covered with sheets of polyurethane
  with air space in between the two sheets to act
  as an insulation .
• Also glass and polyester can be used.

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Greenhouse Materials

• Frame work components
• Slash-sill provides a base for the glass.
• Eave plate sits on side post supports roof
  members.
• Gutter-collect runoff water and take it away from
  the building.
• Drip gutter-condensation that forms on the inside
  of the glazing go to the ground.

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• Slash-bars must carry weight of glazing material,
  snow, and wind.
• The bar-caps hold glazing in place located on the
  exterior of the greenhouse.
• Purloins run the length of the greenhouse to
  support the slash bars
• Framing materials must be strong, light, and be
  able to cast a shadow.

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Climate control

• The heating requirement of a greenhouse depends
  on the types of plants in the greenhouse.
• The greenhouse heating must be adequate to
  maintain the desired temperature day or night.
• Site location is often the deciding factor in the
  type of fuel used. In some regions natural gas
  has been a cheaper source of energy then other
  fuels.

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Climate Control

• 1. Heating
• The requirement for heating a greenhouse resides
  in the task of adding heat at the rate of which
  it is lost.
• Heat is lost by conduction.
• Unit heaters are often referred to as forced air
  heaters.

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Fuels

• There are many types of heating oil, gas, wood,
  or electric.The heat can be distributed by forced
  hot air, radiant heat,hot water or steam.
• To keep greenhouses warm in the winter install
  fans to keep the heat circulating .

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Controls
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Heating Systems
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Air circulation

• Without the fans the hot air rises and the cold
  air settles around the plants.
• A small fan that blows 3 feet air in a min. is
  equal to one quarter of the air volume.
• In a small greenhouse you should place the fans
  diagonally opposite corners the goal is to
  develop a circular pattern of air movement .

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Heating and Cooling Ducts
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Ventilation

• Ventilation is the change from old air to new
  air.
• Natural ventilation is when you have vent in the
  ridge line of the roof.
• Mechanical ventilation - an exhaust fan to move
  the air out one end of the greenhouse while it is
  sucked in the other end.

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Continue

• Ventilation needs may vary because with weather
  and seasons.
• First you must decide how much the greenhouse
  will be used.
• In summer one half the air amount needs to be
  changed.
• In the winter 20 to 30 of air volume changes.

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Continue

• By using LS screens you can deflect solar
  radiation as needed.
• With a shade retention system you can open the
  side walls and or roof of the structure .

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LS Screens
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Water systems

• Water is an essential need.
• Hand watering is one way
• Automatic system can be designed to water as
  needed.
• Time clocks and mechanical evaporation can be
  used to control watering systems.