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

2. Greenhouses ■ 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

3. G REENHOUSE S TRUCTURES

4. Detached houses ■ Quonset ■ Curved (half moon) roof bars ■ Covered with plastic or fiberglass panels

5. Lean to ■ Roof slopes in one direction only ■ Built against other greenhouses or buildings ■ Generally faces south

6. Even span ■ Roof is equal in width and pitch on both sides ■ Most commonly used as a single greenhouse ■ Clear span, truss supports, no columns

7. Even span

8. 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

9. Uneven span

10. Detached houses-Advantages ■ Easy to program and maintain temperature ■ Easy to ventilate without exposing the plants to blasts of cold air

11. Detached house-disadvantages ■ Requires more energy to heat and cool ■ Higher initial cost

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

13. Barrel vault ■ Quonset houses set on sidewalls ■ Height of sidewall range from 7’-10’ depends on crops

14. Dutch-Venlo ■ Ridge and furrow construction ■ Highest percentage of light transmission

15. Saran-covered ■ Used to reduce the intensity of bright sunlight in frost free areas ■ Mainly used for florist crops

16. Connected houses-advantages ■ Require less land area ■ Less construction materials ■ Heat loss is less

17. Connected houses-disadvantages ■ Snow build-up in connecting gutters ■ Gutters shade parts of the greenhouse

18. Greenhouse Equipment and Controls ■ Heaters- gas or electric ■ Thermostats-controls the temperature, should be at plant level ■ Timers- for lights, shade cloth, irrigation, etc.

19. Greenhouse Equipment and Controls ■ 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

20. Greenhouse Equipment and Controls ■ 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

21. Greenhouse Equipment and Controls ■ 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

22. Greenhouse coverings ■ 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. Greenhouses coverings ■ Acrylic panels ■ Energy efficient ■ Impact resistant ■ Available in a variety of widths and lengths

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

25. Greenhouses coverings ■ Solexx panels ■ Flexible ■ Twin wall ■ 3-6 mil thick ■ Opaque ■ Relatively expensive

26. Greenhouse plant terms ■ 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

27. Greenhouse plant terms ■ 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

28. Greenhouse plant terms ■ 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

29. 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 contain peat moss, perlite and vermiculite and are sterile, weed, insect and disease free.

30. Containers ■ 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.

31. Containers ■ 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

32. Containers ■ Plastic pots ■ 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

33. Containers ■ Clay pots ■ Made of porous ■ Can be glazed ■ Various sizes and shapes

34. Containers ■ 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.

35. Greenhouse Production-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)

36. Greenhouse Production-Seeds ■ 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 (2 nd leaves), prepare to transplant ■ Loosen media to prevent breaking roots and stems of seedlings

37. Greenhouse Production-Seeds ■ 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

38. Greenhouse Production-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 hold in the sterile soil ■ Stick cuttings into the hole ■ Gently push soil around cuttings

39. Greenhouse Production-Cuttings ■ Place under greenhouse benches for a couple of days to lessen shock ■ Grow in a sunny location in the greenhouse

40. B EDDING PLANT PROBLEMS

41. Cultural disorders ■ Seed germination problems ■ Improper temperatures ■ Over watering or under watering ■ Chemical residues in soil ■ Seed planting depth ■ Low quality seeds

42. Cultural disorders ■ Seed germination solutions ■ Maintaining proper temperatures ■ Maintain proper moisture levels ■ Chemical free soil plant at proper depth ■ Use high quality seeds

43. Cultural disorders ■ 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

44. Cultural disorders ■ Uneven growth problems ■ Poor mixing of soil ■ Uneven moisture levels ■ Unlevel flats ■ Uneven bottom heat ■ Poor grading of seedlings

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

46. Cultural disorders ■ Tall and spindly growth problems ■ Too much nitrogen fertilizer ■ Overwatering low light intensity ■ High temperatures

47. Cultural disorders ■ Tall and spindly growth solutions ■ Use the correct amount of nitrogen ■ Reduce frequency of watering ■ Lower temperature ■ Provide more light ■ Use a growth retardant such as B-Nine

48. Diseases ■ 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

49. Pests ■ Pest problems ■ Plants or seedling missing caused by slugs, snails or roaches

50. Pests- Pest Problems ■ Holes in the leaves damaged leaves or missing parts ■ 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

51. Pest Problems (cont.) ■ 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

52. Pest Problems (cont.) ■ 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

53. Pests

54. ■ Pest solutions ■ 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.

55. Pests ■ Pest solutions ■ 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

56. Pests ■ Pest solutions ■ 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

57. G REENHOUSE MAINTENANCE

58. Structure ■ Painting (wooden (rot) and metal (rust) structures) as needed ■ Flooring (gravel, wood, cracked concrete) replace as needed ■ Doors (steel, wood, metal) repair as needed

59. Replace covering ■ 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

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

61. Pest Control ■ Weeds, Insects, Diseases- set up a maintenance schedule

62. P LANT MAINTENANCE

63. 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