Presentation on theme: "Greenhouse Management Unit 1. Why a Greenhouse? 1. To grow crops out of season 2. To grow crops not adapted to the locality 3. To speed up the growth."— Presentation transcript:
Greenhouse Management Unit 1
Why a Greenhouse? 1. To grow crops out of season 2. To grow crops not adapted to the locality 3. To speed up the growth of crops
What are commercial greenhouses used for? 1. Fresh flowers-flowers which are cut from the plant prior to sale (roses, mums, carnations, etc.)
2. Flowering Plants- flower bearing plants which are sold in a pot (chrysanthemum, etc.)
3. Green Plants- (foliage plants) - plants sold in a pot and valued more for their foliage than their flowers (Ivy, Rubber Trees, Ferns, etc.)
4. Bedding Plants - young plants sold for planting around the home (Vegetables, Impatiens, Marigold, etc.)
5. Vegetable Production-grown to maturity in a greenhouse (Tomatoes, Lettuce)
6. Woody Ornamental Propagation Reproducing more plants such as: azalea, forsythia, gardenia, etc.
Terms Greenhouse – a structure that is covered with a transparent material that allows sufficient sunlight to enter for the purpose of growing and maintaining plants.
Future of the Greenhouse Industry Growing demand for greenhouse crops Expect increased production of green plants, flowering plants, bedding plants Increased awareness of interior & exterior landscapes Potted plants are competitive on a more local basis due to difficulties and expense of long distance transportation
What role do greenhouses have in the U.S. and in agriculture? 1. Variety of products with many uses 2. Employment Opportunities 3. Economy- Sell almost $20 BILLION in floriculture products/ year 4. Fulfill an emotional need in people
Main Careers in Greenhouse Management Basics 1. Grower 2. Wholesaler 3. Retailer How do these jobs differ?
Careers…. 1. Grower Produces crops for sale to wholesalers Has expertise in producing one or more crops (like poinsettias or chrysanthemums) Generally do not market or advertise
2. Wholesaler Sells a wide range of crops and products to retail businesses Serves as a supermarket for the retailers to buy supplies
3. Retailer Sells products to the general public Location is important for marketing Includes many types of businesses Florist Shops Retail Greenhouses General Retail Stores
BASIC GREENHOUSE STYLES A. BASIC STYLES B. EXAMPLES OF GREENHOUSE USES C. BASIC GREENHOUSE COVERINGS D. COMMON FRAMING MATERIALS
A. BASIC STYLES 1. EVEN SPAN 2. GOTHIC ARCH 3. QUONSET 4. RIDGE AND FURROW 5. LEAN-TO 6. COLD FRAME
TERMS TRUSSES- composed of rafters, chords and struts that support the roof
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
1. EVEN SPAN
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
2. 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
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
5. LEAN-TO ATTACHED TO EXISTING BUILDING USUALLY ON THE EAST OR SOUTH SIDE Benefits: Less roof support needed Heating is usually less expensive Disadvantage: Limited space
Inside Shed Lean-To
Brick is an Example of Side walls (Lean-to is BOTTOM ONLY)
COLD FRAME NO HEATING OR COOLING MECHANISMS SHAPE IS OFTEN CONFUSED FOR QUONSET WILL TALK ABOUT MORE IN A LATER UNIT
Greenhouse Uses 1. Hobby or Home Use small Lean-To or Dutch types 2. Botanical Gardens make plants available to the public Preserve rare plants Like a “zoo for plants”
Greenhouse Uses (continued) 3. Retail Greenhouse at home and garden centers Have displays and examples of plant uses 4. Production House Not as eye appealing Large areas under roof More crowded spaces Entire houses and areas for a 1 type of plant
RETAIL AND PRODUCTION GREENHOUSES ARE CONSIDERED TO BE COMMERCIAL GREENHOUSES
Basic Types of Coverings 1. GLASS 2. FLEXIBLE PLASTIC FILMS 3. RIGID PLASTIC SHEETS
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
LEXAN USED ON OUR GREENHOUSE DOUBLE PANEL SMALL VERTICAL CELLS GOOD INSULATION DURABLE
Framing Materials 2 MAIN MATERIALS METAL WOOD MORE TOMORROW
Greenhouse Systems A. Heating B. Cooling C. Ventilation D. Watering
Heating Systems 1. Boilers 2. Unit heaters 3. Radiant or infrared heaters 4. Terms: BTU
Heating Systems Things to keep in mind: Optimum temperature ranges from degrees, depending on the plant stages Night temperature often from degrees
1. Boilers A.K.A- Centralized Usually used to heat larger greenhouses (15,000 sq ft or more) Burns fossil fuels to create steam or heat water (coal, oil, natural gas) Pipes are used to distribute heat 2 Types a) Steam systems b) Hot water systems Provides more constant heat
Hot Water or Steam Distribution
2. Unit Heaters A.K.A. LOCALIZED Used for smaller greenhouses Convection heat- to heat the air Distribute heat by fans or convention tubes Most burn natural gas Modine Heater is a common brand Can operate independently
3. Radiant Heaters AKA- Infrared Heater Infrared Heat Lamp creates heat Radiant Heat: IR warms surfaces (plants, benches, sidewalks, soil) The warm surfaces in turn warms the air The air is not directly heated Heaters are overhead 20 to 30 feet apart Fueled on gas or electricity
4. Terms BTU (British Thermal Unit) Heat required to raise 1 lb. of water 1 o F Used to measure and compare ability of heating systems
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)
SHADE CLOTHES- often used to supplement cooling/vent systems Available in a variety of colors and shading abilities
1. NO COOLING 1. Inside temperature of greenhouse can exceed 140 degrees F. 2. Plants will die within a short period of time.
2. NATURAL VENTILATION 1. Roof vent opens to allow hot air to escape to outside. 2. Door or other opening must be left open to provide for incoming air from outside to replace exhausted air. 3. On hot summer days temperatures can rise 20 to 30 degrees above outside temperature. 4. Recommended for mild climate areas only.
3. FAN & SHUTTER COOLING 1. Outdoor air is introduced through motorized inlet shutters. 2. Hot air is exhausted by exhaust fans. 3.Temperature inside house can be maintained within 10 degrees of outdoor temperature. 4. controlled by thermostat.
FAN & SHUTTER COOLING
SHUTTERS AND FANS
FAN & SHUTTER COOLING
4. FAN & SHUTTER COOLING with SHADE CLOTH Similar to fan & shutter cooling Differences: 1. Shade cloth is placed over exterior of greenhouse or suspended from wires placed on inside. 2. Temperature inside house can be maintained within 3 to 4 degrees of outdoor temperature
FAN & SHUTTER COOLING with SHADE CLOTH
5. Evaporative Cooling 1. Outdoor air is cooled by Evaporative Cooler (located outside) and discharged into greenhouse. 2. Hot air is exhausted through outlet shutters which operate automatically 3. Temperature inside house can be as much as 10 to 15 degrees cooler than outdoor temperature. 4. controlled by thermostat.
6. EVAPORATIVE COOLING (Fan & Pad) 1. Outdoor air is drawn through pad cooling system located on one end wall of the greenhouse. This cool air enters into the greenhouse. 2. Hot air is exhausted by fans mounted on the opposite end wall of the greenhouse. 3. Temperature inside house can be as much as 10 to 15 degrees cooler than outdoor temperature. 4. controlled by thermostat.