Module 2 Flashcards
Greenhouses
Define a greenhouse
A structure with a transparent covering
What did Roman slaves make greenhouses out of?
Sheets of mica
When were greenhouses built in Europe?
1200s somewhere in Europe (Gino says Italy)
What are 2 plants introduced into greenhouses in the 1600s and what were their origins?
Oranges - China
Pineapple - South America
What structure became popular in Europe in the 1600s? Describe the structure.
Orangeries. Orangeries prioritized heat over light for plant growth, therefore were not fully transparent but designed to conserve heat.
What is the name of the structure built in 1851 in London for the Great Exposition? and what materials was it made of?
Crystal Palace
Glass and iron
What happened to the greenhouse in NY, built in the 1800s?
burned to the ground! as did Crystal Palace :(
What are the 3 types of greenhouses? Describe each briefly.
- Attached: attached to house or building
- Freestanding: built on their own and connected to their own utilities
- Connected: several greenhouses connected together
What are the 3 types of attached greenhouses:
- Lean-To: 7-12’, uses utilities of house, limited ventilation, lack of sunlight (should be on S or E side of house), temp control is challenging
- Even-span: one end is attached to building, more costly than lean to; can be lengthened in segments
- window mounted: projects 1-2’ from window, attached to S or E side of house, low cost, convenient
What are the four possible roof types for freestanding greenhouses?
- quanset (rounded/domed)
- gothic (curved with point)
- uneven span (one side of roof longer than other)
- even span (even sides of roof)
What are the benefits of a connected greenhouse? (3)
- Less construction materials since it doesn’t have walls
- Less heating required overall
- Easier to move through
What are the drawbacks of a connected greenhouse?
- more land required
- difficult to accommodate different environmental conditions
The larger the greenhouse the more ______ the temperature is.
Stable
What are the 3 roof types on a connected greenhouse
Barrel vault, Gutter connected/Ridge and furrow, Sawtooth
Name 5 types of greenhouse coverings:
- Glass
- Fibreglass reinforced plastic
- Film plastic
- Polycarbonate
- Acrylic
What are the advantages and disadvantages of glass coverings?
Advantages:
- best light transmission, close to 100%
- easy to maintain and long lasting
Disadvantages:
- requires thick and strong frame construction
- higher cost of heating because transmission of heat is easy through glass.
Tempered glass is ____x stronger than regular glass and can be _______.
2-3x, curved
What does PAR stand for?
Photosynthetically Active Radiation
What are the advantages and disadvantages of fiberglass reinforced plastic?
Advantages
- 88% PAR
- more light diffusion than glass
- lightweight, strong, hail resistant, and flexible
Disadvantages
- degradation from UV is quicker than glass.
- could collect dust and pollution
- very flammable, higher insurance rates
What are the advantages and disadvantages of film plastic?
Advantages
- cheap initial cost
- light frame
- low fuel costs
- reasonably good light transmission
Disadvantages
- short lifespan of 1-4 yrs (UV inhibitors increase lifespan)
- condensation on inside surface might attract pathogens and cause reduction in light transmission
What’s one way to improve conservation of heat in a film plastic greenhouse?
Double wall plastic: air between layers to improve conservation of heat. Use squirrel cage fans to create layers of insulation.
What are the advantages and disadvantages of polycarbonate covering?
Advantages
- not flammable
- 2 or 3 layers make it very damage resistant
Disadvantages
- 79% PAR
What are the advantages and disadvantages of acrylic coverings?
Advantages
- 83% PAR
- breakage resistant
Disadvantages
- very flammable
Name the 7 structural parts of a greenhouse:
- Ventilators
- Trusses
- Ridge
- Purlin
- Sash bar
- Eave
- Anchor support post
Draw a greenhouse and label the 7 parts.
draw it!
What are 3 ways to heat a greenhouse:
- Steam or hot water through fin pipes
- Forced air heaters hanging from roof (can be dry)
- Infrared Radiant (IR) heaters (heats only objects NOT the air)
What is necessary to maintain uniform air temperature in a greenhouse?
Good air circulation
What is the most efficient layout for ventilation?
In a circular blowing arrangement for optimum movement of air
What is the difference between ventilation and cooling?
Ventilation: moving mass of air
Cooling: reducing temperature of mass of air
Describe 3 types of ventilation
Natural ventilation is when warm air escaping the greenhouse, usually from above, creates a negative pressure, allowing cool air to enter through vents, usually on sides of greenhouse
Fan tube ventilation: a fan blows air through a tube with holes, air exits through the holes
Mechanical ventilation: fan at one end, louvers (window with blind-like horizontal slats) at the other end, cool air comes through shutters on the other end
Describe fan and pad cooling:
One end of greenhouse contains fans, the other side has pads made of cardboard or metal. Water drips through pads as the fan pushes air in from outside. Water takes on the heat and becomes a vapour which removes some heat. Functions similarly to perspiration or transpiration!
What are 2 additional types of greenhouses?
Cold frame: covering over plants
Hot bed: heating source beneath plants
What direction should the short side of the greenhouse face?
Always in the direction of prevailing winds
What does AOI stand for?
Angle of Incidence: angle of material relative to light, determines how much light reflects off of material
Half a greenhouse attached to a building is known as a(n) _____
lean-to
A freestanding greenhouse with a curved roof that comes to a point at the ridge is known as a(n) _______ greenhouse
gothic
________ involves fans drawing warm air out of the greenhouse while outside air is cooled as it enters the greenhouse through moistened pads.
Fan and pad cooling
A(n) _____ allows plants to grow in a sheltered environment while providing bottom heat.
hot bed
_______________ is important to maintain uniform temperature in a greenhouse.
good air circulation
______________ do not heat the air, but the objects that its rays hit.
Infrared radiant heaters
______________ consists of two layers of plastic separated by an air layer which acts as insulation.
Double wall plastic
This type of greenhouse covering is 2-3 times stronger than normal glass and can be bent:
tempered glass
This type of greenhouse covering ahs good light transmission and better light diffusion than glass, but it’s susceptible to UV light degradation and is flammable:
Fibreglass reinforced plastic
_________ are openings in the greenhouse to allow warm air to escape and cooler air to enter.
Ventilators
________ greenhouses require less construction material, heating, and land than freestanding greenhouses per unit area.
Attached
Freestanding greenhouses should be oriented with the short ends facing:
W and E
Attached greenhouses should be oriented with the connected side attached to the ____ side of a building.
N
What are the considerations for a greenhouse location? Clue: MATUZLE
Market
Accessibility
Topography and drainage
Utilities
Zoning regulations
Labour supply
Expansion
