Greenhouse Misting and Misters
Misting is an essential element of the modern greenhouse, and there are a great number of different misters or foggers available from greenhouse suppliers. There are three main types of misters - ultrasonic, centrifugal and direct. Of these the former is purely ornemental and used to produce a surface misting effect on mostly indoor ornamental fountains.
Direct misting makes use of the residual water pressure. This can be installed as a permanent feature in the greenhouse either by attaching the misting heads to the inside of the greenhouse roof, or by a series of risers planted at intervals among the beds or propagation benches.
They may also be attached to the interior walls of the greenhouse at such a height as to enable the mist to reach benches and beds. Mist heads for this system are available which give a coverage of 360, 180 and 90, thus making it easy to cover all parts of the greenhouse. The system is supplied with water through a garden hose, and the higher the residual pressure of the water the better the misting effect will be.
This system of misting can have an electric timer placed in the water supply line, eliminating those continual trips out to the greenhouse to turn on and off the water. The advantage of this system is that it is cheap - though low water pressures will tend to produce tiny droplets of water rather than a fine mist.
By far the most common is the centrifugal mister - powered by electricity these can either be connected permanently to the water system or can have their own integral water tank. In this system water is forced centrifugally through small holes which forces the creation of very fine droplets (as small as 20 microns) and this mist is blown into the surrounding atmosphere by means of a strong fan. The centrifugal mister can also be integrated with an electric timer, thus allowing the mister to come on automatically at a predetermined time.
It is most essential to have a misting system of some sort in your greenhouse. This is the only way that you will be able to effectively control the humidity and to prevent the greenhouse's temperature from rising out of control in the hot afternoon sun. Be careful not to overdo the amount of water you add to the ecosystem in winter as it could lead to mould or other moisture related disease setting in, there being little or no evaporation into the atmosphere in the cold months.