It is an undisputed fact that control
of humidity provides qualitative as well as commercial advantages in nursery business.
The usual applications are propagation techniques where seedlings or cuttings are propagated
(see also Vegetative Propagation) - maybe not so well known are applications for sales areas or breeding
The following possibilities are reviewed:
The shown examples are sales areas in glasshouses.
(Gartenbau Doll, Nonntaler Hauptstraße, Stadt Salzburg and Gartenbau Lederleitner "Roman
Market Hall" Old Stock Exchange Vienna)
The water - provided by our humidification system
- will not cover the total water need of the plants on sale; however their appearance in
these sales areas are much better.
The plants stay fresh for a longer period, the leaves
show more intensive colors.
Moreover the sales area provides a fresh climate, comfortable
to all visitors.
According to the chosen control settings the fogging can be set to morning
dew (following sunrise) as well as during the day with an interval control system able to
adapt to all timing needs; another option is control by hygrostat.
The fogging system
operates automatically and can be utilized round the week (also on closing days) by means
of a 24-hour clock-system.
If the fogging nozzles are mounted on a high level and the
timing interval is set to short but effective intervals no moisture will befall the customers
- usually they regard the fogging effect as dramatic and interesting.
With little effort
small jungle-scenarios can be constructed in the sales area - simulating cloud-forest landscapes
where fog is drifting over water.
One limitation however arises: plants in bud
should be placed at somewhat different locations - due to the perfect climate they would
blossom too fast...
Cooling and Climatization
By evaporating microscopic fog droplets in hot
dry air the surrounding air can be cooled considerably.
This effect - in physics called
"adiabatic cooling" or "evaporation cooling" - can be applied in areas
where plant-production during the hot summer-season is desired but virtually impossible.
As examples of many successfully running plants we have chosen the nursery Tarcik near Tehran (Iran)
and the nursery Canaris in Cyprus.
To provide the optimal cooling effects some criteria
have to be fulfilled - which are listed synoptically:
the fog droplets have to be extremely
small to be able to hover, this means a droplet size of maximal 30 micron (= 0,03 mm diameter).
simple fogging will result in a damp
hothouse climate, therefore substantial air exchange must be provided; ideally a total
exchange of the air volume every minute.
The higher the outside (intake) air temperature
the smaller the cooling effects.
any gardener will know that each plant
- according to its individual profile - will grow actively only up to a certain temperature.
A lesser known fact is that this temperature can be surpassed with rising humidity.
The most important parameter is the
temperature on the leaf-surface, not the surrounding air temperature.
performed by the Institute for Plant-Physiology at the University of Vienna (Prof. Dr.
Bolhar-Nordenkampp) have proven that the surface-temperature of the leaves can be as
much as 10°C lower as the surrounding air !
The cooling effects of fogging in a
glasshouse can create thermic air circulations, if the fogging nozzles are placed optimally.
(please refer also to "air movement in a humidified space").
If all these conditions can be met
the following improvements (currently demonstrated by 18 of our plants on Cyprus) can
With outside temperatures of more than 40°C and a relative humidity
of 40-45 % humidification inside a glasshouse near the saturation point (90-95% relative
humidity) the inside air temperature will be reduced to at least 30°C.
will be even lower, active plant-growth is still no problem.
This cooling principle will work even
better in really hot climates (above 42°C) as experienced in areas in Africa or Middle
East, where the relative humidity of intake-air is considerably lower (for instance in
parts of Saudi Arabia or Iran as low as 15-20% relative)
Summer temperatures in Central Europe
are usually below 32°C even on extreme summer days - therefore in most cases the
installation of fans is not necessary.
Intensive fogging with increased static ventilation
(open side- or top-flaps) can prevent burning of the plants very effectively.
- in coastal areas of hot countries where summer brings high humidity of up to 80% the
described methods of cooling can become ineffective .)
In addition we want to mention that
slight shading decreases heat intake by radiation;
the hovering fog droplets accomplish
this effect without any other means.
Application of Additives
Fungicides, Pesticides, Fertilizer and other
additives are necessary but cost-intensive. Application should be as effective as possible.
If these additives can be applied in liquid form their application can be accomplished with
a fogging system. This method provides several advantages :
Application can be accomplished fully
automated with our fogging plants
No personal observation is needed
The hovering fog, which penetrates
even dense foliage, provides highly effective application
Example : Glasshouse for Anthurium mother-plants in the
"Municipal Reserve Gardens" Vienna
The responsible gardeners report that they had
to perform up to 6 sprayings a year by conventional methods.
After switching application
to the fogging system only two applications with a reduction of the needed spraying material
to approximately the 1/6 part of the original amount !