and
Other Growing Structures
Ward Upham
Modified By Dennis Morgeson

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?

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

Coldframes & Hotbeds
 Coldframes

No supplemental heat
 Hotbeds

Supplemental heat.

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

Supplemental Heat
 Manure
 Electric cable

Coldframe & Hotbed

Conserving Energy

Conserving Energy

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

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

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

Overwintering Plants
 Coldframes

Overwintering Plants
 Greenhouse

Greenhouse?
Discarded crates
 Did buy plastic

Overwintering Geraniums

Heater

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

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

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

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

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

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

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

Types of Greenhouses: Pit

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

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)

Types of Greenhouse Coverings
Glazing
Glass
Sheet Poly
$/Sq Ft Life Light Trans
$2 - $7 > 25 yrs 77% double
$.18 - $.20
3 – 4 yrs 76% double
Polycarbonate $1.75 – 2.50 20-25 yrs 83% double
Acrylic $1.50 – 3.50 20-25 yrs 90% double
Above info from University of Arkansas

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

Plycarbonate, Acrylic, Fiberglass
 Panels
 Roles

Sheet Poly (Plastic) http://www.simplifiedbuilding.com/blog
/using-snap-clamps-to-build-agreenhouse-for-under-150-video/

Plans
 http://bioengr.ag.utk.edu/extension/extpub s/PlanList97.htm

Greenhouse Environment
 Heating
 Cooling
 Air circulation
 Ventilation

Ideas?
http://www.ericsprojects.com/?page_id=228

Double Use? Chicken Tractor
Too

Ideas

Kits?

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

Air Circulation
 Fans
 Helps cut down on disease

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

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

Cooling
 Shade cloth
 Often reduces sunlight by about 50%.

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.

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

Benches

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.