Greenhouse
Shading Guidelines Keeping
the greenhouse cool is accomplished by obtaining
a balance of shading, ventilation and humidity.
Providing the proper amount of each is the secret
to a cool greenhouse. Here are some guidelines
for shading: Shading will be 40% more effective when installed
on the OUTSIDE of the greenhouse. Improve cooling
by suspending the fabric 4″ to 9″ above the glazing
surface. (For SolarGro greenhouses, see our Stand-Off
Kit #2090.) Shading installed INSIDE the greenhouse will protect
your plants from sunburn, but because of the “greenhouse
effect” the sun’s energy will be trapped in the
greenhouse and overheating can result. Radiant/reflective
shading (Revolux #2172) recommended. Materials
The
fiberglass shade screen is attractive and
rolls up well. It has a life of 5-6 years as a
roll shade, longer as a fixed panel. Knitted plastic shades are popular because
of their light weight and easy handling. They
do roll up easily and do not ravel when cut to
size. Life of the material is 5-10 years. Black or green polypropylene is very durable
(lasting 8-15 years) and is available in a wide
range of densities. The dark green lath-weaving
pattern is more attractive for residential applications.
This material does not roll up easily. Reflective (foil ribbon) shading is recommended
where exposure to sun and heat is very high. Life
of 3-5 years. Liquid Shading
Compounds Shading “paint” is popular where neat appearance
is not a major concern. The compound comes as
a concentrate and can be thinned with water to
the desired shading density. Density A density number is the percentage of light blocked
by the shade. The following can be used as a general
guide: 30% – Snapdragons, Chrysanthemums, Geraniums
45%
– Lilies, Bedding Plants, Caladiums
50% – Azaleas, Begonias, Camellias, Gloxinias,
African Violets, Poinsettias
55% – Pachysandra, Ivy, Orchids
60% – Diffenbachia, Stag Horn Fern, Rhododendron
70% – Fern, Anthurium, Dracaena, Philodendron
75% – Palms, Chinese Evergreen Experience has shown that 40 to 60% density is
satisfactory in temperate zones, with the higher
densities of 70 and 80%, and reflective shading,
used in the Southern states. Consider using a
high-density shade on the roof, and a lower density
shade on the walls. A Light Meter (#6639) is a
valuable tool in determining the proper amount
of shading. Shade
Installation The easiest method is to drape the shade over
the greenhouse and secure it with lines through
grommet clips (#2040) that snap onto the edges
of the shade. If you have roof vents, fasten the
shade loosely to allow the vents to open. Snap
Hooks #1447 can be used to secure shading to greenhouse
glass. | 
