Greenhouse Management

							Greenhouse Management
Objective 1.1
Explain why the nursery industry is one of the most
advanced sectors of agriculture
   Growers must be expecting in all of the following areas:
   Soil and its properties
   Watering and fertilizing
   Temperature and photoperiod control
   Lighting
   Pest management
   Harvesting
   Storage
   Marketing
   Grading
   Legal issues and employee management
Objective 1.2
Explain why growers often use
artificial lighting.
    To extend the length of the growing day
Objective 1.3
Explain why it is important to
properly maintain the heating
and ventilation systems.
    The heating and ventilation system
     reduces diseases and provides the
     optimum range for plant growth.
    Two diseases include:
        Botrytis
        Mildew
Objective 1.4
List and explain the various skills a grower must have in the greenhouse
industry.

   Growing
      Watering, temperature, fertilizing, pest management and lighting.

   Mechanical skills
      Construction and maintenance of facilities.

   Marketing skills
      Selling, advertising and maintaining quality of crop after it is harvested.

   Administrative
      Employee issues, daily business task.

   Laws
      Taxes, permits and regulations, and zoning.
Objective 1.5
List and explain the various
types of growers.

    Propagators
    Cut flowers
    Potted plants
    Seed suppliers
    Bulb suppliers
   In charge of all phases of propagation
    (production)
   Determines what to cut, when to cut
   Lighting
   Temperature
   Watering
   Pest management
                       Duties
   Grower: in charge of one or several
    greenhouses
   Lead grower: in charge of several growers.
   Range Superintendent: carries out the orders of
    the owner and oversees the work of the head
    grower, growers and assistants.
   Production manager: in charge of growing the
    crop. They order all of the plant materials,
    supplies, and fertilizers.
                    Grader
   In charge of grading
   Post harvest handling and storage
   Packaging
   Shipping of plants and flowers
   They also order the cartons,containers
    and packaging materials.
                  Manager
   Oversees the sorters
   Graders
   And packers
Objective 1.6
Explain what type of care should be
given to cut flowers

    Cut flowers need special care to keep
     the flower looking fresh.
Objective 1.7
Identify the section of the nursery
industry that is highly mechanized.

      Nursery potted plants
                     Unit 6:
Control of the Greenhouse
               Environment


      Greenhouse Management
Objectives
   Objective 6.1
    Identify the cost associated with greenhouse
    production.
   Objective 6.2
    Explain the greenhouse effect.
   Objective 6.3
    Identify the types of fuels for heating a
    greenhouse.
   Objective 6.4
    Define BTU.
   Objective 6.5
    Identify the types of hot water heating systems.
   Objective 6.6
    Explain the types of heat distribution in a greenhouse.
   Objective 6.7
    Demonstrate how to calculate surface area of a
    greenhouse.
   Objective 6.8
    Calculate BTU requirements for a greenhouse.
   Objective 6.9
    Calculate the amount of pipe needed to heat a
    greenhouse.
   Objective 6.10
    Explain how boilers are rated.
   Objective 6.11
    Explain the function of greenhouse ventilation.
   Objective 6.11a
    Identify the diseases are caused by high
    humidity in the greenhouse.
   Objective 6.12
    Identify the various types of cooling systems.
   Objective 6.13
    Calculate the size of cool cell needed for a
    particular greenhouse.
Objective 6.1
Identify the cost associated with
greenhouse production

 Labor
 Heat

 Water

 Fertilizer &
  Supplies
Objective 6.2
Explain the greenhouse effect
   Light strikes the
    cladding and
    undergoes diffraction.
   The light bounces off
    the floor and other
    structures and is
    trapped by the
    cladding.
   This results in a
    positive flow of
    energy.
Objective 6.3
Identify the types of fuels for heating
a greenhouse

 Gas
 Fuel Oil

 Coal

 Electricity

 Wood

 Solar Energy
Objective 6.4
Define BTU
   BTU (British Thermal
    Unit):
     One BTU is the
      quantity of heat
      required to raise
      the temperature of
      one pound of water
      one degree
      Fahrenheit.
    Objective 6.5
    Identify the types of hot water heating
    systems

   Gravity flow
     Uses steam to flow
      throughout the system.
     As the water turns to
      steam it rises.
     As it cools, it condenses
      and returns to the boiler
      located at the bottom of
      the system.
Objective 6.5
(cont.)
   Motorized
    Accelerated
    Systems
     Uses pressure
      to force hot
      water
      throughout the
      system.
Objective 6.6
Explain the types of heat distribution
in a greenhouse
   Natural Convection
     Radiation of heat
      from a heat source.

   Forced Convection
      The use of a fan to
       distribute heat
       throughout the
       greenhouse
Objective 6.7
Demonstrate how to calculate
surface area of a greenhouse

   Walls
    L x W

   Gable Ends
     T= ½ x B x H

   Roof
    L x W

        W= a2 +b2=c2
   Step 1
     Calculate the surface area for one of the side
      wall.
     Multiple your answer by two since the wall on
      the opposite side is the same size.
   Step 2
     Calculate the surface area for the bottom
      portion of one of the end walls.
     Multiple your answer by two since the wall on
      the opposite side is the same size.
   Step 3
     Calculate the surface area of the gable.

     Multiple by two since the opposite end is the same
      size.
   Step 4
     Determine the width of the roof by using a2+b2=c2.

     Take the square root of c and multiple by the length
      of the greenhouse.
     Multiple your answer by two since the roof on the
      opposite side is the same size.
   Step 5
       Add all of the steps together for a total
        surface area of the greenhouse.
    Objective 6.8
    Calculate BTU requirements for a
    greenhouse
   BTU= H
     H= Ka(t1-t2)

     K= heat transfer coefficient for the cladding.

     a= square feet of exposed surface area of a
      greenhouse.
     t1= desired inside temperature in Fahrenheit

     t2= Outside temperature in Fahrenheit.
      (Expected low)
 Add 10% to your final answer.
 This is due to loss of heat caused by
  openings in the structure itself.
   BTU requirements = 1000

     1000 x 10%= 100

     1000 + 100= 1,100 BTU’s
Objective 6.9
Calculate the amount of pipe needed
to heat a greenhouse

    Finned Pipe
     Length of pipe = BTU’s needed

                        800

       Length of pipe = BTU’s needed
                          160
Objective 6.10
Explain how boilers are rated

   1 Boiler
    Horsepower =
    33,475 BTU/Hr.
     Objective 6.11
     Explain the function of greenhouse
     ventilation

1.   To reduce air
     temperature
2.   To exchange air with
     CO2 for
     photosynthesis
3.   To reduce relative
     humidity to reduce
     disease
Objective 6.11a
Identify the diseases are caused by
high humidity in the greenhouse

 Mold
 Fungus
Objective 6.12
Calculate the size of fan needed to
ventilate a greenhouse

   Step 1
     Determine the volume of the greenhouse

        [(W x He) + W x Hr] x L

                         2
            W = Width of the greenhouse
            He = Height of the side wall
            Hr = Height of the gable
            L = Length of the greenhouse
   Step 2
     Divide the volume by 15,000 cfm’s.

       cfm’s = cubic feet/minute
 Objective 6.12
 Identify the various types of cooling
 systems


 Fans

 Cooling Pads
 High-Pressure

    Fog Cooling
 Shade Cloth
Objective 6.13
Calculate the size of cool cell needed
for a particular greenhouse

   Step 1
    Volume of the Greenhouse* = Square
      Feet of Pad
          150 cubic feet

    * Use the formula for calculating volume
      of a greenhouse.
   Step 2
    Apply Correction Factor for Fan-to-Pad
      Distance is Less than 100’.

Distance in Feet             Correction
      20-30                        1.7
      30-45                        1.56
      45-60                        1.42
      60-85                        1.28
      85-100                       1.14
Example Correction

 Volume = 25,000 ft3
 Distance = 47 ft

 Pad Size = 25,000/150 = 166.66

 Correction Factor = 1.42

 Final Size After Distance Correction =

    166.66 ft2 * 1.42 = 236.66 ft2
   Step 3
    Apply correction for elevation above sea
    level.

    Elevation          Correction
    to 1000 ft             1.0
    1000-2000 ft           1.04
    2000-3000 ft           1.08
    3000-4000 ft           1.12
    4000-5000 ft           1.17
    5000-6000 ft           1.22
    6000-7000 ft           1.27
Example Correction
   Volume = 25,000 ft3
   Distance = 47 ft
   Elevation = 1,524 ft
   Pad Size = 25,000/150 = 166.66
   Correction Factor = 1.42
   Final Size After Distance Correction =
      166.66 ft2 * 1.42 = 236.66 ft2
   Elevation Correction =
      236.66 ft2 * 1.04 = 246.13 ft2