Site Slope and Aspect
· South facing for maximum sun exposure
· Avoid obstructions -- hills, trees to the south
o Need uninterrupted sunlight
· Gentle slope
o Avoid greater than 20% (10°) slope due to
§ Soil erosion
§ Difficulty moving plants and equipment
· Good water supply
o Need 1 quart per square foot per day
§ This is 10,000 gallons a day for a one acre greenhouse
o No (or very little) toxic minerals:
§ Arsenic
§ Molybdenum
§ Boron
§ Fluoride
§ Manganese
o Avoid high mineral loads of
§ Iron
· Not a growth problem for plants, but tends to coat everything
· If you have it, use a different irrigation system; eg bottom up
§ Calcium
· Can also for precipitants on leaves, clog water systems, etc
· Adequate soil drainage
o Potential ground water contamination
§ Must comply with federal, state and borough regulations
o Use ebb & flow irrigation to help minimize waste water
o Watch out for permafrost!
§ Often found in areas of poor drainage
§ Will cause (often serious) structural damage & problems
o Wetlands: restricted use
· Best sites:
o Deep, well drained loams
o Sandy or gravelly loams
o Accessible water table
o Good supply of soil and peat
§ Best if on property
§ Peat in Alaska is produced anaerobicly and is lower in quality with lower uniformity than that found in the lower 48. No sphagnum peat here. Ours holds water too well, is prone to algae attacks.
o Natural windbreaks or hills on N and NW sides
o Dependable supply of energy
§ Electricity and fuel for heating
o Air pollution
§ Blocks sunlight
§ Deteriorates structures
· Acid rain pits glass & fiberglass
o Pits collect dust
o Reduces light transmission
o Telephone access
o Access to roads with year-round maintenance
o Proper zone and building codes
§ Usually greenhouses = agriculture
§ Will also dictate fences, public access, signs and easements
o Local tax structure
§ Temporary plastic houses are sometimes taxed as permanent structures & sometimes not!
o Site location must fit clientele
§ Retail needs more floor space, easy access
§ Wholesale needs more greenhouse space, access is not as critical
o Plan for expansion and future
o Labor supply
§ Schools kids are often a good source of labor
§ Needs lots of seasonal labor
· April, May, June (in Alaska)
§ Many child labor laws do not apply to agriculture, especially if the kids are your own
o Site must permit proper orientation of greenhouse
§ Single greenhouse located N of 40° north latitude
· Ridge runs E to W
· Low winter light enters along side
§ Below 40° N orient N-S or E-W due to high sun angle
§ Large connected greenhouse
· All latitudes
· A shadow occurs because of ridge (N roof & gutter of each greenhouse)
· If ridge is oriented N-S shadow moves across floor
· If oriented E-W shadow is stationary; locate walkways here if possible
Hobby greenhouses
· Less emphasis on public access
· S exposure--or close to it
· Drainage critical
· Traffic and kid's play areas
o With especial consideration for broken windows
· Building ordinances
o Especially in city limits
· Soil conditions only important if crop is grown in the ground
Develop a planning worksheet
· List the following
o Cropping system: bedding plants, pot plants, cut flowers, woody ornamentals, vegetables, etc
o Growing period: year round vs seasonal
o Growing system: floor, fixed benches, moving benches, hanging baskets, in the ground, etc
o Production unit: pots, flats, stems (as in roses), vegetables, etc
o Annual production (# pots, flats, stems, etc)
o Growing media: soilless, soil mix, purchased, site mix, hydroponic
o Marketing system: wholesale, retail, both
o Marketing period: year round, seasonal (dates)
o layout
Identify the components of the layout
1. Head House
o N side of greenhouse
o Attached to the greenhouse
o May contain
· Heated workroom with benches
· Rest rooms, locker area and lunch area
· Storage space for pots, fertilizers
· Refrigerator
· Grading tables or packing areas
· Administration offices
· Boilers, controls for greenhouse heating and ventilation and lights
o No long term pesticide storage
o Large service doors
· Minimum width: 2 feet wider than vehicle
· Minimum height: 12 feet
o Concrete floors are best
o An estimate of the amount of head house space needed: approximate head house area needed per 1000 square feet of greenhouse area:
|
Greenhouse size (square feet) |
Head house size (square feet per 1000 square feet of greenhouse; ie divide greenhouse size by 1,000 and multiply by this number) |
|
<10,000 |
175 |
|
10,000-40,000 |
150 |
|
40,000-80,000 |
100 |
|
80,000+ |
75 |
2. Storage area
· Must be dry, squirrel and rodent proof
· Convenient access
· Easily accessible to vehicles
· Consider using clear span buildings
o Minimum width 24 feet
3. Service roads -- all buildings connected by roads
4. Sales area -- people like greenhouses
· Hint for unheated storage area; it takes ~ 1 week to thaw 1 meter of peat
5. Parking areas
6. Production area
· Includes greenhouse
o Cold frames
o Hot bed
o Lath house
o Field production areas
o Bulb clears (root clears)
o Growing rooms
2/1 Slides/comments:
-Cold frame usually 3x6 ft.
-One sided usually
-2 sided oriented n/s
-Commonly used to harden off stuff
--1 wk hardening off
--Lids off in day in gradually increasing amounts; on at night
-Can be used in warmer areas to overwinter stuff
-Sash covers 'lid'; can be made of -many materials ,but glass tends to break
-Don't want cold frames very high; need to reach over side.
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