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

Oakcrest High School, Mays Landing NJ

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 you’re retailers

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 – 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

Detached Greenhouses

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

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

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

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.

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.

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

Curvilinear Greenhouses

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

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.

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.

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.

– 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.

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.

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.

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 .

Controls

Heating Systems

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 .

Heating and Cooling Ducts

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.

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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 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 .

LS Screens

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.