Dry water may fit into this category but it's a genuine phenomenon that has aeroponic enthusiasts thinking of growing to infinity and beyond.

What we refer to in the growing industry as 'Dry Water' is actually a dry fog that behaves as a fluid in its gaseous phase.  The fog, which is produced by an ultrasonic fog generator, is actually less than 5 micron droplets; very 'dry' when you compare it to atmospheric fog which is anywhere from 12 to 15 micron droplets. The ultrasonic fog generators used to produce the dry ice like effect in decorative fountains is around 20 microns and definitely not adequate for growing applications .

A silent storm is brewing over the outstanding results growers are seeing when their plants get fogged.  A grower who recently switched from a conventional aeroponic system to the fog method of feeding was amazed by the simplicity of fogging "It's such an easy and efficient way to grow. My plants thrive in this clean, almost sterile environment.  My garden hasn't  been troubled by whiteflies or spidermites,  a constant battle in my regular aeroponic garden."

The 'dry water' or 'fog' produced by an ultrasonic fog generator has so many applications for horticultural use. The fog (less than 5 microns in size) or fluid in a gaseous state is capable of deep penetration of minute spaces.  This eliminates the "free water" which contributes to contamination, disease and pollution of solutions using traditional methods in agricultural applications. By adding easily soluble substances to the water, the user can carry out chemical or nutrient treatments which help to provide an improved product.

Aeorponics is considered the purest form of plant cultivation.  Oxygen and nutrients are delivered to the plant's root zone in ideal proportions creating an atmosphere for vigorous and healthy growth

 In the traditional aeroponic garden, roots are fed nutrient through a continuous fine mist while they are suspended in the air.  A series of spray heads are connected to a high powered pump that runs on continuous cycles to keep roots moist. Because a very fine mist is required, about 20 micron droplets, the misting nozzles or spray heads in an aeroponic garden often clog with the salts and calcium contained in the nutrients. Trying to maintain an aeroponic system can be a constant source of frustration for the grower.  If a sprayer becomes clogged it must be cleaned quickly as plants will suffer immediately from deprivation of oxygen and moisture.

Another drawback of traditional aeroponic gardening is the 'pooling' of solution that occurs when the run off spray from the roots gathers in the trough.  This can cause contamination and root disease.  Roots may also suffer 'wet feet,' become waterlogged, and drown. 

A constantly monitored, well maintained aeorponic garden is capable of continuous production.  Set up and operating costs tend to be quite high.  A minimum of 60 PSI (pounds per square inch) pump is usually required to generate a mist capable of running eight to ten misting nozzles. This type of pump is expensive to buy (anywhere from $400.00 - $600.00) and run.  The pump must be cycled on a timer which creates a large energy draw every time it fires up.

An ultrasonic fog machine eliminates the need for extensive recirculation equipment used in aeroponic nutrient feeding. The fogger produces a fog with ultrasonic vibrations of a piezoelectric crystal. Each particle of mist is very uniform and less than 5 micron droplets.  A nutrient solution may be used in the fogger to directly target the root zone.  The fine fog flows freely in the root chamber making its way to the roots as well as small root hairs.  The complete penetration  by the fog saves significantly on the amount of nutrient required.  A traditional aeroponic garden will run with an EC (Electro Conductivity) of 2000.  With the fogger it is sufficient to operate with an EC of 1200 -1500, up to a 40% savings on nutrients.  The outside of the roots are dry to the touch therefore discouraging bacterial contamination and root rot.  Root mass development is strong and healthy, disease resistant resulting in a more viable crop.

When a pair of reading glasses were placed in an enclosed grow area while the fogger was running, no condensation or moisture  appeared on the glasses surface.  However, when a tomato cutting in a rockwool cube, severely wilted  from dehydration was placed in the chamber it showed an immediate response.  The cutting quickly returned to its robust stance and within a short time began to develop roots.

Using fogging in a propagation environment has been credited with faster root development and a lower mortality rate than with conventional methods.  Less damping off was witnessed while stem and leaf growth were accelerated.  Fogging shows infinite potential for cuttings as well as tissue culture propagation methods. 

The ultrasonic fog machine is also very effective for foliar feeding in an enclosed area.  Unlike hand sprayers the fog is able to infiltrate all areas of the plant.  Foliar nutrients are absorbed by all the pores in the top and underside of the leaf as well as the stem.  

A water fogger machine works like a multi function humidifier.  The mist created is so fine it gets into very minute areas, however, the surface remains dry eliminating the threat of mould and mildew. 

Tests conducted on administering insecticide through fog have been very successful. 

Residue analysis indicate that a high percentage of contact insecticide was delivered to the lower leaf surface where whitefly and other soft bodied insects tend to hide.  The fogger provided good control of whiteflies on test plants in a greenhouse while using much reduced rates of imidacloprid insecticide. The fogger may have application for greenhouse commodities. For example, commercial plants such as poinsettia are good whitefly hosts, but have low damage thresholds for aesthetic reasons.  This fogger may help growers manage whiteflies on these and other greenhouse commodities with low level of contact insecticides.  Overall tests have shown that plants treated with fog laced insecticide require a fraction of the recommended dose.

Another application for the ultrasonic fog generator is the cleaning and sterilization of the growing environment and equipment.  The fog produced by the unit has all the properties of a gas and as such is an ideal vehicle for the transportation and deposition of 35% H₂0₂ (Hydrogen peroxide.) a sanitization agent.  Fungusides and virusides can also be added to the fogger to pre-treat growing surfaces.  As an added bonus, the fogger is also a water purifier!  Pathogens and bacteria cannot survive the ultrasonic vibration of the piezoelectric crystal.

The ultrasonic fogger produces fog through vibration that is faster than the speed of sound.  To fog a 3' X 4' X 8' area requires approximately ½ litre of liquid eg; nutrient solution, per hour.  No pressure is needed as gravity feeds solution from a remote reservoir to the fogger.  A simple float valve regulates the amount of solution being delivered to the unit. 

Ideal humidity should be kept around 85%.  Even this fine of a fog will condensate if humidity is allowed to climb above 100%.  A humidistat is necessary to ensure that the growing area does not exceed this level. Temperature may hamper the efficacy of the fogger. An ideal temperature should not go above 75 degrees F.

The fog generated by the ultrasonic fog generator is so fine that it is not apparent and therefore has no effect on the light reception by the plants. In other words the fog will not affect the lumens received by plants from their light source.  Lamps and electrical equipment are not affected by the fog

Even a perfect idiot with high business ethics can see that the fogger will be a mandatory option in any grow room!  So kick back, have a lite beer, enjoy some nutritious junk food and let your plants enjoy the benefits of dry water!