Transcript Greenhouse Management

Greenhouse Management
4.02 - Understand greenhouse structures,
production and maintenance
Greenhouses
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The “Greenhouse Effect”- collects and stores heat
from the sun (radiant heat)
Provides a protective environment to grow plants
Many detached houses can be used as connected
houses
GREENHOUSE STRUCTURES
Detached houses
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Quonset
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Curved (half moon) roof bars
Covered with plastic or fiberglass panels
Lean to
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Roof slopes in one direction only
Built against other greenhouses or buildings
Generally faces south
Even span
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Roof is equal in width and pitch on both sides
Most commonly used as a single greenhouse
Clear span, truss supports, no columns
Even span
Uneven span
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One side of the roof is longer than the other side for
southern exposure
Usually found on hillsides with one wall
May have a solid north wall
Uneven span
Detached houses-Advantages
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Easy to program and maintain temperature
Easy to ventilate without exposing the plants to blasts
of cold air
Detached house-disadvantages
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Requires more energy to heat and cool
Higher initial cost
Connected Houses
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Ridge and Furrow
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Even span structures placed one after the other
No side walls
Barrel vault
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Quonset houses set on sidewalls
Height of sidewall range from 7’-10’ depends on crops
Dutch-Venlo
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Ridge and furrow construction
Highest percentage of light transmission
Saran-covered
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Used to reduce the intensity of bright sunlight in frost
free areas
Mainly used for florist crops
Connected houses-advantages
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Require less land area
Less construction materials
Heat loss is less
Connected houses-disadvantages
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Snow build-up in connecting gutters
Gutters shade parts of the greenhouse
Greenhouse Equipment and Controls
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Heaters- gas or electric
Thermostats-controls the temperature, should be at
plant level
Timers- for lights, shade cloth, irrigation, etc.
Greenhouse Equipment and Controls
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Evaporative cooling systems
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Most effective method for cooling a greenhouse
Constructed of thick corrugated cardboard
Reduces watering due to higher humidity created by
evaporation from the dripping water in the cool pad
Greenhouse Equipment and Controls
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Exhaust fans- pull hot air from the greenhouse
Vents- located at the opposite end of the exhaust fan.
Vents open to allow fresh air in the greenhouse
Circulation fans- circulates air in the greenhouse even
when the exhaust fan is not running. Provides a
uniform temperature throughout greenhouse
Greenhouse Equipment and Controls
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Misting systems- cools the greenhouse and provides a fine
mist for seeds and cuttings
Overhead irrigation system- waters greenhouses or shade
houses but may not give the deep watering some plants need
Drip Irrigation- tubes with emitters go to individual pots for
water. A very efficient way to water.
Lights- provide additional lighting for plants on cloudy or
wintery days. Black cloth will block light
Greenhouse coverings
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Greenhouse film (polyethylene film)
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3-6 mil thick
Standard to UV treated. UV film keeps Ultra Violet rays
from damaging plants
Inexpensive
Long lasting and easy to replace
Greenhouses coverings
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Acrylic panels
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Energy efficient
Impact resistant
Available in a variety of widths and lengths
Greenhouses coverings
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Polycarbonate panels
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Twin wall panels
Corrugated panels
Available in a variety of widths and lengths
Relatively expensive
Greenhouses coverings
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Solexx panels
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Flexible
Twin wall
3-6 mil thick
Opaque
Relatively expensive
Greenhouse plant terms
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Annual- plant that completes their life cycle in one
year
Biennial- plants that complete their life cycles in two
years
Perennial- plants that live more than two years
Greenhouse plant terms
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Sow- to plant seeds
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Direct sowing- starting seeds directly into the soil or pots.
No transplanting necessary
Indirect sowing- starting seeds in flats, trays, etc. and
transplanting them into the soil or other pots
Greenhouse plant terms
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Media-soil
Deadheading- removal of spent or dead flowers
Pinch- removal of the top portion of a plant to make the plant
more compact
Full sun- at least 6 hours of sun each day
Part shade- morning sun until 12:00 noon, no afternoon sun
Shade- a few hours of morning sun, filtered light or full shade
Bedding Plant Soils/Media
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Vermiculite- expanded mica, sterile
Perlite- expanded volcanic rock
Peat moss- decomposing parts of sphagnum moss typically
found deep in bogs
Sand- finely ground stone
Bark- tree bark usually shredded or ground
Commercially prepared soil mixes contain peat moss, perlite
and vermiculite and are sterile, weed, insect and disease
free.
Containers
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Flat- plastic tray usually for planting seeds or holding cell
pack (10”W x 20”Lx 2 1/2 “D)
Cell pack- several small cell like pots of plastic molded
together. Four common sizes are 804, 606, 1206 and 1801
Peat pots- insulate the roots, can be planted directly into the
soil, breaks down when planted, roots grow through peat
material
Eco pots- expensive, made from plants and vegetable oil.
Containers
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Jiffy 7- compressed peat moss covered in a fine
mesh. Expand when soaked in water and can be
planted directly into the soil. Used for sowing seeds or
rooting cuttings
Containers
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Plastic pots
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Standard pot is the same width and the top as it is high
Azalea pot is ¾ as high as its top diameter or width
Vary in sizes and shapes
Containers
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Clay pots
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Made of porous
Can be glazed
Various sizes and shapes
Containers
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Hanging baskets
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Plastic, wire, cloth pouches (living walls)
Wire hanging baskets may require some type of liner
Varies in sizes 8”, 10”, 12”, 16”, etc.
Greenhouse Production-Seeds
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Select seeds to sow. Read specific instructions for
selected seeds.
Sow selected seeds in a sterile seed starter media.
Cover if necessary
Water seeds from the bottom or mist
Cover seeds with a humidity dome (if necessary)
Greenhouse Production-Seeds
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Place seed flat on the bench in the appropriate light
and/or on propagation mats if needed
Check seeds daily for moisture
Once seeds germinate and true leaves appear (2nd
leaves), prepare to transplant
Loosen media to prevent breaking roots and stems of
seedlings
Greenhouse Production-Seeds
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Hold plants by their leaves. Do not hold the stem as they bruise easily
Transplant seedlings into saleable containers slightly deeper than it
grew in the flat
Water newly transplanted seedlings
Provide appropriate light for plants
Create a pest free environment and control as needed
Harden off (drop the temperature and reduce water) before moving
plants out to shade houses or protected areas
Greenhouse Production-Cuttings
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Select plants for cuttings (English ivy, pothos,
wandering jew, etc.)
Make cuts below the node (area on the stem where
leaves grow), remove leaves (if necessary) dip in
water and dip in rooting hormone, tap lightly
Make hold in the sterile soil
Stick cuttings into the hole
Gently push soil around cuttings
Greenhouse Production-Cuttings
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Place under greenhouse benches for a couple of days
to lessen shock
Grow in a sunny location in the greenhouse
BEDDING PLANT PROBLEMS
Cultural disorders
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Seed germination problems
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Improper temperatures
Over watering or under watering
Chemical residues in soil
Seed planting depth
Low quality seeds
Cultural disorders
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Seed germination solutions
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Maintaining proper temperatures
Maintain proper moisture levels
Chemical free soil plant at proper depth
Use high quality seeds
Cultural disorders
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Fertilization problems
■ Lack of nutrients
■ Root injury
■ Improper pH in soil
■ Excessive fertilization
Fertilization solutions
■ Testing soil
■ Applying correct amount and kinds of nutrients
■ Correct pH
Cultural disorders
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Uneven growth problems
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Poor mixing of soil
Uneven moisture levels
Unlevel flats
Uneven bottom heat
Poor grading of seedlings
Cultural disorders
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Uneven growth solutions
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Properly mixing soil
Even watering
Placing flats level
Replace damaged propagation mats or cables
Grading seedlings by size
Cultural disorders
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Tall and spindly growth problems
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Too much nitrogen fertilizer
Overwatering low light intensity
High temperatures
Cultural disorders
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Tall and spindly growth solutions
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Use the correct amount of nitrogen
Reduce frequency of watering
Lower temperature
Provide more light
Use a growth retardant such as B-Nine
Diseases
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Disease problems
■ Damping off- seedling fall over causing the stem to rot
■ Botrytis- lower leaves are brown, rotting and drying out
Solutions
■ Use sterilized soil
■ Use fungicides to control diseases
■ Improve air circulation
■ Increase air temperature around plants
Pests
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Pest problems
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Plants or seedling missing caused by slugs, snails or
roaches
Pests- Pest Problems
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Holes in the leaves damaged leaves or missing parts
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Aphids- green soft bodied, winged or non-winged,
sucking insect
Mealybugs- white cottony, sucking insects
Spider mites- red body pest with eight legs
Scale- brown, hard shelled sucking insect
Pest Problems (cont.)
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Thrip- small translucent, sucking insect
Whiteflies- powdery insects with four white wings, sucking
insect
Fungus gnats- thrive in moist wet environments, larba feed on
plant roots and new callused tissue
Leaf miner- larva produces mines by burrowing and feeding
between the upper and lower epidermis. This allows air in and
changes the leaf color in the mines to pale green or silver
Pest Problems (cont.)
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Cutworms- can enter the greenhouse as moths and
lay eggs. Cutworms chew stems at the soil level
Slugs- 2-3” slimy brown body, burrowing pests,
damaging roots and leaves of plants
Caterpillars- eat plant parts, chewing insects
Pests
Pests
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Pest solutions
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Monitor plants on a regular basis for insect problems
Identify pest
Use beneficial insects- parasitic wasps, ladybeetles,
praying mantis, lacewings, or use an insecticide
Set up a pesticide program. Use pesticides if necessary.
Pests
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Pest solutions
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Aphids- ladybeetles, praying mantis, insecticidal soap
Mealybugs- insecticidal soap
Spider mites- predatory mites, miticide
Scale- outdoor use dormant oil, greenhouse use alcohol
on individual insects or insecticidal soap
Thrip- parasitic wasps, insecticidal soap
Pests
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Pest solutions
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Whitefly- whitefly trap (sticky board), insecticidal soap
Fungus gnat- watch moisture levels in the greenhouse,
biological control such as Bacillus thuringiensis (Bt)
Leaf miner- pyrethroid (attacks the exoskeleton of insect)
Cutworm- Bt
Slugs- traps, handpick
Caterpillar-Bt
GREENHOUSE MAINTENANCE
Structure
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Painting (wooden (rot) and metal (rust) structures) as
needed
Flooring (gravel, wood, cracked concrete) replace as
needed
Doors (steel, wood, metal) repair as needed
Replace covering
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Glass replace when cracked or broken
Fiberglass replace when damaged
Greenhouse film (polyethylene film) replace when torn
or damaged
Shade cloth- cover or take off depending on season
Equipment repair
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Heater- motor, fan blades, gas/electric lines, etc.
Ventilation system- belts, motor, etc.
Irrigation- clogged emitters, holes in tubing
Lighting- electrical, bulbs
Pest Control
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Weeds, Insects, Diseases- set up a maintenance
schedule
PLANT MAINTENANCE
Plant maintenance
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Water plants regularly, avoid watering in the middle of
the day during the summer
Set up a fertilizer schedule
Check for insects and diseases and treat
appropriately
Control weeds
Pinch plants to encourage fullness if necessary
Keep the greenhouse clean