1. Understand Greenhouse Management
4.02 Understand greenhouse structures, production, and maintenance.

2. Purposes of Greenhouses
The “greenhouse effect” collects and stores heat from the sun or radiant heat.
Provides a protective environment to grow plants.
Many detached houses can be used as connected houses.

3. Detached Houses-Quonset
Curved (half-moon) roof bars
Covered with plastic or fiberglass panels

4. Detached Houses-Lean to
Roof slopes in one direction only
Built against other greenhouses or buildings
Generally faces south

5. Detached Houses-Even Span
Roof is equal in width and pitch on both sides
Most commonly used as a single greenhouse
Clear span, truss support, no columns

6. Detached Houses-Uneven Span
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.

7. Advantages of Detached Houses
Easy to program and maintain temperature
Easy to ventilate without exposing the plants to blasts of cold air

8. Disadvantages of Detached Houses
Requires more energy to heat and cool
Higher initial cost

9. Connected Houses-Ridge and Furrow
Even span structures placed one after the other
No side walls

10. Connected Houses-Barrel Vault
Quonset houses set on sidewalls
Height of sidewall ranges from 7’-10’ depends on crops

11. Connected Houses-Dutch-venlo
Ridge and furrow construction
Highest percentage of light transmission

12. Connected Houses-Saran-Covered
Used to reduce the intensity of bright sunlight in frost-free areas
Mainly used for florist crops

13. Advantages of Connected Houses
Requires less land area
Less construction materials
Heat loss is less

14. Disadvantages of Connected Houses
Snow build-up in connecting gutters
Gutters shade parts of the greenhouse

15. Greenhouse Equipment and Controls

16. Temperature Control Heaters-gas or electric
Thermostats-controls the temperature and should be at plant level
Evaporative Cooling Systems
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

17. Temperature Control Exhaust fans-pulls hot air from the greenhouse
Vents-located at the opposite end from 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 the greenhouse.

18. Timers
Timers should be used to control lights, shade cloth, irrigation, etc.

19. Irrigation
Misting system-cools the greenhouse and provides a fine mist for seeds and cuttings
Overhead irrigation system-waters greenhouses or shadehouses but may not give deep watering some plants need
Drip irrigation-tubes with emitters go to individual pot for water. A very efficient way to water.

20. Lights
Provide additional lighting for plants on cloudy or wintery days. To block out light for certain crops in the greenhouse use black cloth.

21. Greenhouse Coverings

22. Greenhouse Film (polyethylene film)
3-6 mil thick
Standard to UV treated. UV film keeps ultra violet rays from damaging plants
Inexpensive
Long lasting and easy to replace

23. Acrylic Panels Energy efficient Impact resistant
Available in a variety of widths and lengths

24. Polycarbonate Panels Twin wall panels Corrugated panels
Available in a variety of widths and lengths
Relatively expensive

25. Solexx Panels Flexible Twin wall 3-6 mil thick Opaque
Relatively expensive

26. Greenhouse Plant Terminology

27. Life Cycles Annual-plants that complete their life cycles in one year
Biennial-Plants that complete their life cycles in two years
Perennial-plants that live more than two years

28. Planting Methods Sow-to plant seeds
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.

29. Plant Manipulation Deadheading-removal of spent or dead flowers
Pinch-removal of the top portion of a plant to make the plant more compact

30. Light Requirements Full sun-requires 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

31. Bedding Plant Soils/Media
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 usually contain peat moss, perlite and vermiculite and are sterile, weed, insect and disease free

32. Containers

33. Flats/Cell Packs
Flat-Plastic tray usually for planting seeds or holding cell packs. 10”Wx20”Lx2 ½”D (may vary in size)
Cell pack-several small cell like pots of plastic molded together. Four common sizes are 804, 606, 1206, 1801

34. Natural Pots
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
Jiffy 7-compressed peat moss covered in fine mesh. They expand when soaked in water and can be planted directly into the soil. Can be used for sowing seeds or rooting cuttings.

35. Plastic Pots Standard pot is the same width at the top as it is high.
Azalea pot is ¾ as high as its top diameter or width.
Vary in sizes and shapes.

36. Clay Pots Made of porous materials Can be glazed
Various sizes and shapes available

37. Hanging Baskets Plastic, wire, cloth pouches (living walls)
Wire hanging baskets may require some type of liner
Varies in sizes 8”, 10”, 12”, 16”, etc.

38. Greenhouse Production

39. Greenhouse Production from Seeds
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).
Place seed flat on the bench in the appropriate light and/or on propagation mats if needed.
Check seeds daily for moisture.

40. Greenhouse Production from Seeds
Once seeds germinate and true leaves (2nd set of leaves) appear, prepare to transplant.
Loosen media to prevent breaking roots and stems of seedlings.
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. (Tomato seedlings-plant to the bottom of the true leaves.)

41. Greenhouse Production from Seeds
Water newly transplanted seedlings.
Provide the appropriate light for the plants
Create a pest free environment and/or control pests as needed.
Harden off (drop the temperature and reduce water) before moving plants out to shade houses or protected area.

42. Greenhouse Production from Cuttings
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 a hole in the sterile soil
Stick cutting(s) into the hole.
Gently push soil around cutting

43. Greenhouse Production from Cuttings
Water the cuttings.
Place under greenhouse benches for a couple of days to lessen shock.
Grow in a sunny location in the greenhouse.

44. Bedding Plant Problems

45. Cultural Disorders Seed germination problems Improper temperatures
Over-watering or under-watering
Chemical residues in soil
Seed planting depth
Low quality seeds

46. Cultural Disorders Seed germination solutions
Maintaining proper temperature
Maintain proper moisture levels
Chemical free soil
Plant at proper depth
Use high quality seeds

47. Cultural Disorders Fertilization problems Lack of nutrients
Root injury
Improper pH in soil
Excessive fertilization

48. Cultural Disorders Fertilization solutions Testing soil
Applying correct amount and kinds of nutrients
Correct pH

49. Cultural Disorders Uneven growth problems Poor mixing of soil
Uneven moisture levels
Unlevel flats
Uneven bottom heat
Poor grading of seedlings

50. Cultural Disorders Uneven growth solutions Properly mixing soil
Even watering
Placing flats level
Replace damaged propagation mats or cables
Grading seedlings by size

51. Cultural Disorders Tall and spindly growth problems
Too much nitrogen fertilizer
Overwatering
Low light intensity
High temperatures

52. Cultural Disorders Tall and spindly growth solutions
Use the correct amount of nitrogen
Reducing frequency of watering
Lowering temperature
Provide more light
Use a growth retardant such as B-Nine

53. Diseases

54. Disease Problems
Damping off-seedlings fall over causing the stem to rot

55. Disease Problems
Botrytis-lower leaves are brown, rotting and drying out

56. Disease Solutions Use sterilized soil
Use fungicides to control diseases
Improve air circulation
Increase air temperature around plants

57. Pests-Problems and Solutions

58. General Pest Problems
Plants or seedlings missing caused by slugs, snails, or roaches
Holes in the leaves, damaged leaves or missing plant parts

59. General Pest Solutions
Monitor plants on a regular basis for insect problems.
Identify pests
Use beneficial insects-parasitic wasps, ladybeetles, praying mantis or lacewings
Use an insecticide

60. Types of Pests
Aphids
Green soft bodied, winged or non-winged, sucking insect
Control using ladybeetles, praying mantis, insecticidal soap

61. Types of Pests Mealybugs White, cottony, sucking insect
Control using insecticidal soap

62. Types of Pests Spider Mites Red body pest with eight legs
Control using predatory mites and miticides

63. Types of Pests Scale Brown, hard shelled, sucking insect
Outdoors control using dormant oil. Greenhouse control using alcohol on individual insects or insecticidal soap.

64. Types of Pests Thrip Small translucent, sucking insect
Control using parasitic wasps and insecticidal soap

65. Types of Pests Whiteflies
Powdery insects with four white wings, sucking insect
Control using a whitefly trap (sticky board) or insecticidal soap

66. Types of Pests Fungus gnats Thrive in moist wet environments
Larva feed on plant roots and new callused tissue
Control by watching moisture levels in the greenhouse and use of biological control such as Bacillus thuringiensis

67. Types of Pests Leaf miner
Larva produces mines by burrowing and feeding between the upper and lower epidermis of leaves. This allows air in and changes the leaf color in the mines to pale green or silver.
Control using pyrethroid (attacks the exoskeleton of the insect)

68. Types of Pests Cutworms
Can enter the greenhouse as moths and lay eggs.
Cutworms chew at the soil level
Control using Bacillius thuringiensis

69. Types of Pests
Slugs
2”-3” slimy brown body, burrowing pests, damage roots and leaves of plants
Control using slug trap or hand pick

70. Types of pests Caterpillars Eat plant parts, chewing insects
Control using Bacillius thuringiensis

71. Greenhouse Maintenance

72. Structure Maintenance
Painting wood (rot) and metal (rust) structures as needed
Flooring (gravel, wood, cracked concrete) replaced as needed
Doors (steel, wood, metal) repaired as needed

73. Replace Covering Replace glass when cracked or broken
Replace fiberglass when damaged
Replace greenhouse film (polyethylene) when torn or damaged
Cover or take off shade cloth depending on season

74. Equipment Repair Heater-motor, fan blades, gas/electric lines, etc.
Ventilation system-belts, motor, etc.
Irrigation-clogged emitters, holes in tubing
Lighting-electrical, bulbs

75. Pest Control
Set up a maintenance schedule for weed, insect, and disease control.

76. Plant Maintenance
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