Transcript Hobby Greenhouses

Hobby Greenhouses
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?
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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
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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

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Least expensive
Easy access
Insulation for and from adjoining structure
 Disadvantages
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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
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More flexibility in location and use
Easy expansion
Private Get-away
 Disadvantages
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More difficult access
Separate utilities must be run
Higher energy costs
Types of Greenhouses: Pit
Pit Greenhouse
 Advantages
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Less energy required to heat and cool
Temperature more constant
 Disadvantages
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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
$/Sq Ft
Life
Light Trans
Glass
$2 - $7
> 25 yrs
77% double
Sheet Poly
$.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
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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.
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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.
The End