Watercress is fun and easy to grow at home. Take a look at our article showing you how to use the grocery store watercress to start your own patch of watercress at home. Hydroponic Water Cress. This is an image of commercially hydroponically grown watercress.
Fog is the extreme of humidity. Humidity control systems add or remove water vapor from indoor air to stay within proper humidity ranges. Humidity control is important for three reasons: 1  It is a large factor in people's thermal comfort.2  Excess moisture in a building can lead to mold and mildew, causing problems for indoor air quality.umidity control systems add or remove water vapor from indoor air to stay within proper humidity ranges. Humidity control is important for three reasons: 1  It is a large factor in people's thermal comfort.
Humidity levels can vary indoors and outdoors. If humidity gets too high indoors, a dehumidifier can be used. When it gets too dry indoors, a humidifier can be used. The amount of water vapor in the air is expressed as relative humidity. It is expressed in percent, as it is the ratio of the amount of water vapor in the air to the total amount of moisture the air can hold at a particular temperature.