What is a mist chamber?
A mist chamber refers to an enclosed structure system where relative humidity is maintained artificially with the help of mist instillations which spray water under pressure at a high level. The formation of fog induces acclimatation and rooting for the plants. Nursery plants that are propagated by cutting are grown in mist chambers. The high humidity levels ensure that the root initiation process is complete and the cooling effect within misting chambers ensures that the cutting is not dried out.
The use of mist chambers results in faster rooting for the cuttings and creates an optimum micro environment in which the root initiation is better. This helps in faster development of the plants and higher success rates with the cuttings. The mist chambers can be automated as the light, temperature and humidity levels can be externally and remotely controlled ensuring that the plants have a conducive environment for growth at all times.
Mist chambers are generally used for vegetative plants and seeds apart from research purposes. These chambers help in reducing the plant moisture loss and can also be extremely supportive in facilitating rooting of leafy cuttings. The size of the mist particles can vary between 50 to 100 micrometers.
Mist chambers can help in rooting of plants such as eucalyptus, bamboo and other medicinal plants and the hardening of tissue culture plants.
Advantages of mist chambers:
• Mist chambers facilitate a faster growth of cuttings and the rooting process
• They help in creating an optimum and appropriate micro environment for the root initiation and development process
• Ensures that the plants are not subject to a pest infestations, pathogens and insect attacks
• They have proven to have higher success rates in the propagation of hard wood cuttings
• Automation and external control of temperature and humidity ensure that the relative humidity can be maintained easily and remotely
• The mist chambers have a long life if installed and maintained properly and can be an extremely successful investment that gives returns quickly
Controls of a mist chamber:
A mist chamber has 5 main control mechanisms that operate together to maintain the relative humidity within the chamber:
- Timer: there are two main types of timers that are installed in a mist chamber. The first timer is used in a mist unit that is turned on in the morning time and turned off in the evening. The second timer operates only during the day time and helps in the production of intermittent mist and intervals that are pre decided. The industry standard for this time is, one minute on and one minute and thirty seconds off.
- Thermostat: A thermostat is used to control the temperature of the mist that is produced and released inside the mist chamber. It ensures that the temperature is maintained and does not become too cold or too hot for the plants to grow.
- Photoelectric cell: This is based on the relation between the light intensity and transpiration rate within the mist chambers. Striking the right degree of balance between both these factors will ensure a conducive micro climate for the roots and cuttings.
- Electronic leaf: an electronic leaf refers to a plastic with two terminals which is placed under the mist alongside the cuttings that in an alternate format promotes the drying and wetting of the terminal to break off the current which further controls the solenoid value of the mist chamber.
- Screen balance: The screen balance refers to a screen made of stainless steel which is attached to a lever with the help of a mercury switch. The mercury switch is tripped in a situation where the mist on water weighs more and is controlled by the screen.
Components of a mist chamber:
A mist chamber consists of various parts as listed below that work together to provide the right micro climate for a conducive process of plant growth:
- Structure: This refers to the external structure of the mist chamber that is generally a galvanized iron frame structure that is enclosed to incorporate the missing systems.
- Plunge propagation bench: This refers to a bench that is generally made of metals like aluminum which provides a framework for the plant cuttings within the mist chamber
- Professional thermostat: This refers to a rod thermostat that helps in gaining an accurate reading of the temperature within the mist chamber
- Soil warming cable: This refers to a cable that is attached to the undersoil area and facilitates in warming the roots. This is connected with the thermostat and the temperature can be monitored and automated.
- Misting systems: This refers to a system that helps in creating and maintaining a warm, damp and humid micro environment that prevents the cuttings from wilting or drying which in turn promotes quick growth of the roots.
- Fogging system: This refers to a system of overhead fogging at the gutter height of the mist chamber to ensure the moisture levels within the chamber remain constant.
- Solenoid valve: This refers to a valve that is opened and closed automatically that allows water to pass through as directed by the electronic leaf controller.
- Other components: These are optional components in a mist system that can be installed based on the requirement of the owner. They include benching systems with fixed or movable tops, seeder machines, climate control sensors, horticulture lights and buffer rooms.
Hardening of plants in mist chambers:
After rooting in the mist chamber, it is important for the rooted cuttings to be hardened for better field existence. Misting should however not stop once the cuttings are rooted as this may lead to death of young plants due to dehydration and drying in accordance with scorching. The weaving off process should be continued and gradually reduced in which the misting system still operates but the number of sprays reduce.
Another method of ensuring the plants survive in a conducive micro environment is by moving them to a greenhouse or a fog chamber where the temperature is maintained at higher degrees and the relative humidity is lower. Whichever mode is chose, the hardening process should be done in a phased manner in order to ensure that the rooted cuttings are planted in permanent locations.