Humidify Your Home

Through emails and especially on forums, I see a lot of questions concerning humidification of the home or growing area of the home, especially as Fall and Winter draw near.   Trying to humidify your home is a worthwhile endeavor – for you, your plants, and your home.

While I cannot give specific brand-name recommendations (I have a Jaybird manufacturing Aquafog 700 in my greenhouse), there are a few guidelines that can be shared:

First, talk to a knowledgeable store salesman and look for something that can put out a sufficient volume of moisture to keep the RH at about 50%-60%. That is a good level for you and the plants, while not being so saturated that furniture damage will likely occur. A moderately-sized “whole house” humidifier out do do the trick, but try to get one that works off of a humidistat rather than one with just high-medium-low controls. (You can add a remote, in-line humidistat easily, if you cannot find one with it.) Remember that your home or apartment is not 100% “tight”, so you will be losing moisture to the surroundings, so purchase a humidifier with a bit of excess capacity.

There are three basic mechanisms used in humidifiers:

  • “Cool mist” or ultrasonic devices atomize the water and force the micro-droplets into the air. Any minerals dissolved in the water will precipitate as a white dust on plants, furniture, and any horizontal surface. The use of pure water prevents that, but some ultrasonic transducers won’t work with it. The mechanical atomization or “buzzing” of the ultrasonic transducer can be a slight problem, but it usually ends up as a mild source of “white noise” that is ignored.
  • “Warm mist” devices heat the water and add moisture to the air in the form of steam. With those, the dissolved minerals tend to build up on the heating element. Pure water solves that problem. Such devices are essentially silent in their operation.
  • A “wick” type of humidifier is typical for the “whole house” device. Typically a cloth mesh belt or sponge is moved through a water bath (sometimes they just stand in it and capillary action draws up the moisture), and air is blown through the mesh to evaporate it. Mineral buildup will occur on the wick, but it tends to be slow, and generally the wicks are inexpensive and easy to replace, so you need not bother with pure water. The fan may produce a low noise level – probably lower than the cool-mist type of humidifier – but it is usually not an issue.

A “do-it-yourself” humidifier can also made with some aquarium-related components – an air stone, air pump, and a tank. Just immerse a very fine air stone (as large as you can accommodate) into a tank of water – the deeper the better, although 12″-18″ is sufficient – and turn on the air. The fine bubbles will be totally saturated by the time the reach the surface, where they will break, releasing the moisture into the air.

Using Science & Logic to Improve Horticulture