Hobby Greenhouses and Other Growing Structures

1. Hobby Greenhousesand Other Growing Structures Ward Upham

2. Questions That Must be Answered • What do you want to accomplish with your greenhouse or other structure? • Start plants early • Extend the season • Overwinter plants • Grow year-round • What can you afford?

3. Start Plants Early • Light Garden for Germination and early growth

4. Light Garden • May want to use bottom heat

5. Light Garden • Use fluorescents 2 inches above top of plants (18 hours light, 6 hours darkness)

6. What if Plants Leggy? • Increase light • Decrease temperature

7. Fluorescent Lamps • T-12 lamp • 1500–1700 lumens last 10,000 to 20,000 hours • Use 40 watts for 48 inch lamp • T-8 lamp • 3400 lumens and lasts 40,000 hours • Use 32 watts for 48 inch lamp • T-5 lamp • 5000 lumens and lasts 30,000 hours • Uses 54 watts for 48 inch lamp

8. Start Plants Early • Light Garden for Germination and early growth • Cold Frame and Hotbed to grow to transplant size.

9. Coldframes & Hotbeds • Coldframes • No supplemental heat • Hotbeds • Supplemental heat.

10. Supplemental Heat • 12 to 18 inches of manure under hotbed with 4 to 6 inches of soil on top • Plant when soil temp drops to 85 degrees

11. Supplemental Heat • Manure • Electric cable

12. Coldframe & Hotbed

13. Conserving Energy

14. Conserving Energy

15. Extend the Growing Season • Hoophouses (High Tunnels) are relatively inexpensive (compared to greenhouses) • Greenhouses ($20/sq ft) High Tunnels ($.50/ sq ft)

16. High Tunnels • Single layer of plastic • No heat or cooling (other than venting) • Irrigation a must

17. High Tunnels • Tomatoes ripen 3 to 4 weeks earlier in spring • Tomatoes can be harvested an additional 3 weeks in the fall.

18. Overwintering Plants • Coldframes

19. Overwintering Plants • Gus’s Greenhouse

20. Gus’s Greenhouse • Wood from discarded crates • Did buy plastic

21. Overwintering Geraniums

22. Heater

23. Growing Year-Round • Considerations • Winter growing difficult due to limited quantity and intensity of light • Winter growing expensive due to fuel costs • Summer growing difficult due to temperature control and watering demands. Need to have some type of shading. • Hobby greenhouses often lack adequate heating and cooling to grow plants year-round

24. Locating a Greenhouse • Sun all day (or most of the day) is best for most (not all) plants

25. Locating a Greenhouse • Sun all day (or most of the day) is best for most (not all) plants • If must choose between morning sun and afternoon sun, choose morning sun • Normally want full sun but may help to shade late afternoon sun during the summer

26. Types of Greenhouses: Lean-to Line Drawing Courtesy of West Virginia University

27. Lean-To Greenhouse • Advantages • Least expensive • Easy access • Insulation for and from adjoining structure • Disadvantages • Size limited by structure • Dirt and insects tracked into adjoining structure • Moisture

28. Types of Greenhouses: Free-Standing Line Drawing Courtesy of West Virginia University

29. Free-Standing Greenhouse • Advantages • More flexibility in location and use • Easy expansion • Private Get-away • Disadvantages • More difficult access • Separate utilities must be run • Higher energy costs

30. Types of Greenhouses: Pit

31. Pit Greenhouse • Advantages • Less energy required to heat and cool • Temperature more constant • Disadvantages • Access more difficult • Need sump pump to get rid of excess water • More expensive to build

32. Glazings • The more light transmitted, the better • For every 1% reduction in light received, there is a 1% reduction in plant growth (unless you are over 3500 foot candles of light)

33. Types of Greenhouse Coverings Above info from University of Arkansas

34. Other Comments • Glass: Heavy and subject to breakage • Poly film: Cheap but short-lived. Must be UV treated. Best if inner layer is IR film that is anti-condensate. • Polycarbonate: Can be scratched but more resistant than acrylic. Also, less flammable than acrylic. High expansion and contraction • Acrylic: Easily scratched, flammable, lower impact resistance than polycarbonate. Also, high expansion & contraction

35. Greenhouse Environment • Heating • Cooling • Air circulation • Ventilation

36. Ventilation • Roof vents can be operated by solar powered • Need vent for cool air (doors or dedicated vents.

37. Air Circulation • Fans • Helps cut down on disease

38. Heating • Gas (7,000 BTU @ $649) • Electric (7,600 BTU @ $324) 240 volt • Wood

39. Heater BTU Rating Needed Varies With • Size of greenhouse (Sq ft and height) • Exposure • Coldest temperature expected • Free-standing or lean-to

40. Cooling • Shade cloth • Often reduces sunlight by about 50%.

41. Cooling • Evaporative (Swamp) Cooler for greenhouses 200 sq ft or smaller. • How well works depends on relative humidity • Cost $550 to $1500 for “box” models.

42. Cooling • Can also place evaporative pads along one side of greenhouse for greenhouses over 200 square feet.

43. Benches

44. How to Water Properly • Allow enough time between watering to allow most of the water to be used. Roots must have oxygen. • Apply 10-15% more water than container will hold to leach salts. All fertilizers are salts.

45. The End