Ventilating Greenhouses: Types Of Greenhouse Ventilation

When the weather gets too hot, venilating your greenhouse can be a critical decision for healthy plants. Plan ahead.

Ventilation System In A Large Greenhouse
(Image credit: phanasitti)

The advantage to growing plants in a greenhouse is that you can control all the environmental factors: temperature, air flow, and even moisture content in the air.

In the summer, and even in other months in warmer climates, keeping the air inside a greenhouse cool is the main goal. When controlling greenhouse temps, directing the flow of air inside and out of the structure will create most of the cooling effect.

There are two ways of ventilating greenhouses, and the best way for your setup depends on the size of the building and your desire to save either time or money.

Greenhouse Ventilation Info

The two basic types of greenhouse ventilation are natural ventilation and fan ventilation.

Natural ventilation - Natural ventilation depends on a couple of basic scientific principles. Heat rises and air moves. Windows with moveable louvers are set into the wall near the roof in the greenhouse ends. The warm air inside rises and stays near the open windows. Wind outdoors pushes cooler outside air inside, which in turn pushes the warmer air from inside the greenhouse toward the outside space.

Fan ventilation - Fan ventilation relies on electric greenhouse fans to move the hot air outside. They can be set into the ends of the wall or even in the roof itself, provided it has moveable panels or spaces to accommodate the breeze.

Controlling Greenhouse Temps

Study greenhouse ventilation online, and compare the two types to decide which one is right for you.

When using natural ventilation, you will need to visit the greenhouse multiple times during the day to check whether the louvers need to open or close more. This is a free system once it's set up, but does take an investment in your time every day.

On the other hand, fan ventilation can be made completely automatic. Set a relay up to turn on the fan once the air inside the greenhouse reaches a certain temperature and you'll never have to worry about ventilation again. However, the system is far from free, as you'll need to give it periodic maintenance and must pay the monthly electric bills for using the fans themselves.

With contributions from