he crop develops a compact appearance with stronger stems.
The response is similar to the use of “brushing” or
“mechanical conditioning” for height control. Proper operation of
open roofs and roll-up side walls lets growers capture natural breezes as a
growing tool to develop crops with strong stems and a compact appearance.
Exposure to gentle breezes has also been shown to help the
plant develop its own natural resistance to insects and diseases. It also
encourages proper development of waxy surfaces on leaves and stems, which help
reduce water loss and provide some protection against insect feeding and
invasion by germinating disease spores. When the plant’s own defenses are
stimulated, the effectiveness of biological predators is improved. So, compared
to structures with stationary coverings, plants grown in open-roof structures
often require fewer applications of pesticides. Natural breezes are free, but
you need a structure that lets you take advantage of them.
Naturally compact plants with strong stems and improved
resistance to pests let the grower reduce or eliminate the applications of
chemical growth regulators and pesticides. This reduces all costs and risks
associated with chemical applications, including: cost of chemicals,
application labor, application equipment maintenance, application
record-keeping, possible phytotoxicity damage to the crop, and possible worker
exposure to chemicals (including possible litigation costs). When your records
prove you have reduced your use of chemicals, you can also request a lower
premium on your liability insurance.
For crops like bedding plants or perennials that will
eventually be used outdoors where they will be exposed to natural breezes,
plants properly grown in open-roof structures are already acclimated to wind.
This eliminates the labor costs and growing space needed to relocate the plants
to a “hardening-off” area before shipping.
Using UV light
Greenhouse glazing greatly reduces or nearly eliminates
exposure of the crop to UV light. The materials that protect the glazing from
damage by UV light also prevent exposure of the crop to UV light.
Exposure to excessive UV radiation can slow growth or directly
damage many crops. However, exposure to sufficient UV light is needed to
encourage the plant to protect itself from radiation. The stronger cell walls,
changes in physiology and thicker, waxy cuticles that plants develop to protect
themselves from exposure to UV light also help protect them from pests and
diseases. Many plants also grow more compact when exposed to UV light. So, just
like grower-controlled exposure to natural breezes, careful exposure to UV
Á light can improve crop quality, reduce the use of chemicals and reduce
costs. Natural UV light is free, but you need a structure that lets you take
advantage of it.
For crops like bedding plants or perennials that will
eventually be used outdoors where they will be exposed to UV light, plants properly grown in open-roof structures are always acclimated to UV light. This
eliminates labor costs and growing space needed to relocate crops to a
“hardening-off” area before shipping.
Using full sunlight
All greenhouse glazings reduce the total amount of light
available to the crop. Stationary
coverings reduce the amount of light all the time, even when a reduction
(shading) is not needed. Under cloudy conditions or in the early morning and
late afternoon hours, shading is usually not needed. Open-roof structures
provide growers with the option to expose the crop to all of the available
light whenever shading is not needed. The extra light can influence crop
Compared to the taller, softer growth with weak stems that
some plants develop when grown in traditional greenhouses, careful exposure to
full-sun conditions when grown in open-roof structures encourages plants to
develop stronger stems, waxy surfaces and a compact growth habit. So, just like
grower-controlled exposure to natural breezes and UV-light, careful exposure to
full sunlight can improve crop quality, reduce the use of chemicals and reduce
costs. Natura