Improved Humidity Control Comes to Greenhouses

Most greenhouse growers fight a continual battle against low humidity and high temperature, which can trigger plant water stress. If humidity drops below 30 percent, the growing process may slow to a halt. The problem can worsen each winter when cold weather reduces the moisture in the air.

To assure consistent quality and production, greenhouse operators and growers are turning from traditional humidification techniques to a new method that dramatically improves humidification coverage, responsiveness and productivity while reducing water/energy use,  maintenance and installation cost.

Plants lose most of their moisture from evaporation through their leaves, and get most of the carbon needed for growth from carbon dioxide through their leaves. Controlling plants’ pores by effectively controlling the climate can result in stronger, healthier plants with more growth potential. In this effort, fog systems are a proven way of providing needed humidification, as well as cooling via evaporation.

The challenge is that humidification coverage must be complete, uniform, and responsive to changing moisture levels in the air. It must keep all plants from getting too dry and too wet. Water vapor collecting in the wrong pattern, in fact, can “fall out” to create areas of wetness while other areas may remain too dry.

In an age of tight budgets and rising commodity prices, thought also needs to be given to reducing water and energy use, and maintenance and installation cost.

A number of traditional misting systems add moisture to the air in greenhouse applications. While these offer benefits, they’ve been limited by drawbacks.

Typical humidification systems leave hot, cold, dry or wet zones, which have a lag time in mixing because the spray is directional.  This causes plant stress, less than optimal health and growth, and can hurt the bottom line.

Among high-pressure fog systems, which create and distribute tiny water droplets based on the humidity level needed in an area, static line systems and vertical fan systems have been common choices.

With static line systems, which mount and align tubes and nozzles to deliver mist, uneven humidification distribution can be a problem. Moisture may not completely or uniformly evaporate into the surrounding air. Nozzles which spray a certain distance and direction can create areas of too much moisture or wetness under a nozzle. Other areas farther from mist-spraying nozzles may receive too little humidification.

With no airstream to spread humidification beyond the nozzle spray areas, it can be difficult to provide complete, uniform coverage and it can take longer to reach desired humidification levels. Water moisture “fall out” can increase water use and over-wet plants — making them more susceptible to disease, fungi and insects — while labor-intensive tubing alignment and mounting can increase installation and maintenance cost.

A vertical fan humidification system adds an airstream to aid air moisture distribution, but a stationary airstream typically covers just a narrow band 25-degrees wide. Like a flashlight’s beam, this leaves many areas outside its focus. Humidification may be relatively slow to diffuse, with pockets of relative dryness remaining. Adding fan oscillation can distribute mist over a wider area, but still leave areas with less humidification while the airflow is pointed elsewhere. Turbulence is also created when airstreams cross, leading to increased “fallout” and water use with diminished humidification.

Air and water humidification systems, combining low-pressure water and high-pressure air to atomize water droplets, also have drawbacks for greenhouse use. These include high upfront costs for nozzles that combine air and water, expensive air compressors, and expensive separate lines for air and water. The cost of maintaining dual air-water systems typically runs high as well.

A Humidification Revolution

For greenhouse operators seeking to prevent growth or quality issues due to dry air-caused plant water stress, our Revolution and Evolution misting fans provide the ideal solution.   We are a member of OFA, an association of floriculture professionals, so we understand what is required and we have systematically addressed the drawbacks of traditional greenhouse humidification and humidty control.

Developed with customer input, our integrated climate control system can to achieve complete humidification of greenhouse areas up to 10,000 cubic feet without “fallout” or wetness.

If, like a flashlight, traditional static lines or vertical fans emit narrow “beams” of humidification, then the Revolution acts like a floodlight, bathing a whole area with humidification.

What’s unique about the technology is how it achieves continuous, even, 360-degree humidification coverage. Hung like a simple ceiling fan, it broadcasts a fine “invisible mist” outward in a horizontal circle along a stream of air. By integrating the horizontal airstream with the fog, its micron-size water droplets stay suspended much farther and longer than traditional systems. This provides better, more even distribution of humidification, more complete evaporation, and virtually no “fallout.” Through flash evaporation temperatures can be reduced up to 30 F, and humidification levels can be maintained near 90 percent.

By broadcasting a focused airstream mixed with fog in a full-circle, the Revolution can quickly eliminate the hot, cold, dry or wet zones that typical humidification systems leave behind.  By minimizing wetting from “fallout” there’s less susceptibility to disease, fungi and insects.

Because the Fogco unit can adapt to humidity or temperature changes up to three times faster than static line systems, plants continue growing longer and healthier within a tighter humidification and temperature range.

Since the unit can adapt quickly to weather changes when used with a thermostat and humidistat, there’s more growing consistency.  It gives growers the precision they need to create and maintain an ideal greenhouse growing environment without peaks and valleys of temperature and humidification.

A 360-degree vented mist system for humidification, the Revolution provides up to five times the coverage of static line systems with less water, maintenance and installation cost. With more even humidification coverage and less “fallout”, the unit can use a significantly smaller pump than traditional systems, which minimizes utility costs.

Compared to static line systems, users of the unit can save up to 35% on water/electricity and up to 75% on water/electricity compared to vertical fan systems.

In a time of budget constraints, the Revolution’s simplified installation can save resources too. Since it hangs like a ceiling fan, it reduces installation and maintenance cost. Its set up eliminates the need to work around poles, perimeters, columns, and changes in floor elevation, reducing labor cost and cutting installation time about 90% compared to static line system installation.

With precise, efficient control of humidification and temperature, the Revolution is making greenhouses greener.  The plants are greener, and so is greenhouse water, energy and labor use. It’s about time.

The Fogco Revolution can be mounted from any overhead structure, used indoor or out, and comes with an outdoor rated fan and powder coated enclosure. The mist system for humidification is portable when mounted from a custom stand. The system is designed to operate with any Fogco pulley-driven or direct-drive 1,000-psi fog pump, and is customizable by choice of appropriate Fogco nozzles.