Greenhouse Care and Crop Protection
Weed control on landscape nurseries has been an on going problem over the years
. Herbicide sprays have been used with success, but crop damage could occur if
during the spraying process material should drift onto plant material or if the
applicator was careless. Herbicide granules could also cause damage if during
application material would get into containers etc. Plastic polyethylene
sheeting (Ground Cover) forms an excellent weed
barrier, however it does not allow water to seep through causing unsatisfactory
working conditions after a rain shower or irrigation.
Thermal Screens are used
primarily in Greenhouse production. The grower can create almost any
environment needed to grow a quality crop. Thermal screens can assist in
controlling day and night temperatures as well as day length.
Crop delays caused by excessive hot or cold temperatures are virtually
eliminated when thermal screens are used along with your greenhouse cooling and
Heating bills go down and cooling systems are more efficient with the
installation of thermal screens.
Gintec's retractable thermal screen system allows growers to obtain climate
control all year. Winter heating bills can be reduced by as much as 50 percent
when screens are closed at night. Once the heat is in your structure, it will
stay longer with the presence of a properly equipped thermal screening system.
Thermal screening systems (shade, heat retention, or blackout curtains) reduce
heat loss by reducing the air volume needed to be heated, creating an attic in
the greenhouse for an insulative air barrier, and reducing the stratification
of heat energy up to the roof.
During the summer month's screens can be deployed over the crop, returning
temperatures back to an optimum growing range.
These cable drive systems are operated by electric drive units with reversing
control and built-in limit switches. They can be operated manually or by
computer. These systems come in a kit form with installation instructions for
installation by the grower.
Ludvig Svensson International BV manufactures OLS
screens. OLS screens are manufactured from HDPE and aluminum strips. OLS
screens are specially designed for use in fixed or roller screen installations
intended for interior or external applications of both glass and plastic houses
The open structure of the fabric allows adequate air replacement between the
two sides. The aluminum strips used reflect the strong sunlight so that the
greenhouse stays cool by day. At the same time, the roller screen reduces heat
radiation at night, resulting in a higher inside temperature.
OLS screens can be applied in the following three ways.
In cover roll installations immediately beneath the ventilators in the
greenhouse. The open structure of the fabric allows good ventilation.
Against the glass on the outside of the greenhouse or at some distance
from it. Solar rays are reflected outside the house with this method.
This produces the largest possible temperature reduction. This method
also offers protection against hail.
Close to the sheeting on the outside of plastic Quonsets. A simple
manually operated system is available for rolling the screen up and
down. The main objectives of this method are: maximum cooling by day
during the summer and countering heat radiation on cold nights.
Use of OLS roll screens therefore limits crop damage through spring and night
frosts as well as hot summer days.
OLS screens are manufactured in 30%, 40%, 50%, 60%, 70%, and 80% shade factors.
An OLS 90% ABRI is also available. ABRI refers to a 2.3mm polyester support
wire knitted into the screen. Standard width is 4.2 meters (13.77'). Lengths
can be cut to specification. Wider widths may be obtained by cutting and/or
sewing combinations together using LS Americas or Gintec Shade Technologies
sewing techniques. OLS screens are used to protect all greenhouse grown crops.