What is greenhouse ventilation?
A greenhouse ventilation system replaces the stale air inside the greenhouse with fresh air. This helps in increasing the quality of plant growth and ensures that the air inside the greenhouse does not get saturated with oxygen. As light hits the walls of a greenhouse, a part of the energy absorbed is converted to heat.
While this energy can easily get into the greenhouse, it is extremely difficult for it to leave the inside of the greenhouse on its own. This energy then creates warmth which may or may not be conducive for the growth of plants. If there are no greenhouse cooling systems in place, the temperature within the greenhouse will keep rising and become extremely high that will destroy the crops.
To balance the increasing temperature in the greenhouse a proper ventilation system must be installed. The design of this ventilation system will determine the maintenance of optimal temperatures for plant growth. A good ventilation system will also help in increasing pollination of the plants and reducing the susceptibility to pests.
What is the need for greenhouse ventilation?
• Temperature control- Too much heat can cause damage to plants. There should always be a system in place that helps the heat escape at all levels.
• Humidity control- Humidity build up inside the greenhouse can also damage the plants. Water that comes off plants should be timely removed to maintain the level of humidity based on temperature.
• Air circulation- Maintaining a proper air circulation will ensure that the temperature is maintained as well as the saturation of elements in the air is combated.
• Provides carbon Dioxide- If Carbon Dioxide is not induced artificially, the ventilation system should ensure that the there is sufficient CO2 for the plants to grow and the air should not end up being oxygen saturated and hinder with the process of photosynthesis.
• Prevents pests- A good ventilation system will ensure that pests don’t multiply as it maintains temperature with low humidity. Pests require warmth and moisture to multiply and a ventilation system combats both these issues.
What are the types of greenhouse ventilation?
There are 2 main types of greenhouse ventilations and the suitability is based on factors such as the size of the greenhouse, cost of the system etc.
- Mechanical Ventilation: This refers to a system where fans are installed inside the greenhouse to exhaust the rising hot air. This system creates a vacuum in which the cold air from outside is pulled inside through louvers on the side walls of the greenhouse. There should be various fans installed through out the greenhouse to ensure proper ventilation. When the fans are installed and operated at the right speed, they can provide the exact temperature for the plants regardless of the outside climate changes.
- Natural Ventilation: This refers to a system where greenhouse curtains and side wall vents are used to maintain the circulation of air inside the greenhouse. A curtain system allows the movement of air across the width of the greenhouse. These systems do not require fans and are more energy and cost effective as compared to a mechanical ventilation system. They can be automated to reduce labor cost and increase operating efficiency.
Both these ventilation system have their own pros and cons and the right kind of system should be chosen after careful consideration of all external factors that may affect the greenhouse now and on a future date.