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Chill Out! Cooling & Ventilation in Your Greenhouse

Greenhouse with Roll-Up SidesIt’s the first day of summer and it’s HOT in the greater part of the country! Maintaining good ventilation in your greenhouse is perhaps the most important elements in keeping your plants happy and healthy this summer and all year long. Ventilation helps your plants in several crucial ways, and without it, you could find your plants (and your spirits) wilting. Ventilation systems affect fresh air flow, temperature control, pollination and even pest problems, and these factors are major determinants of how successful your greenhouse will be.


Commercial Greenhouse 45Fresh air flow plays a huge role in making sure that the plants in your greenhouse have the carbon dioxide they need to photosynthesize. All plants need this in order to thrive, and without proper ventilation in your greenhouse, the lack of circulation will cause the air to become stagnant and stale, resulting in inadequate carbon dioxide levels. You not only need fresh air moving into your greenhouse through vents, but you also need circulation fans to keep the air uniformly moving across all of your plants and an exhaust fan to push the stale air out and encourage more fresh air to draw in.


Did you know that greenhouse plants die more often from overheating than from the cold? Your greenhouse can become too hot for your sensitive plants which will lead to hindered growth, unhealthy and stressed appearance, or eventually death. Uniform temperature all over your greenhouse is important, and can be achieved by having several vents placed evenly throughout. If you live in an especially warm climate and plan on growing in your greenhouse during the summer, you should consider using an evaporative cooling system in addition to your exhaust fan to provide a natural method of cooling and moisturizing the air.


Commercial Greenhouse VentilationIf you notice that some of the plants in your greenhouse are not maturing the way they should be, hindered pollination caused by inadequate ventilation is likely to blame. In your greenhouse, you can’t rely on the natural wind to pollinate your plants. You’re in luck, though, because having good circulation and fans in your greenhouse can simulate the real thing. The flowing air will cause the plants to softly shake, thus allowing pollination to occur. With this gentle air flow you will also see physical signs of improved health in your plants, because it will promote sturdier stems and root systems.


Many growers don’t even consider how ventilation affects pests in their greenhouses, but poor air flow does play a major role. When plants become sick, they are vulnerable to unwanted pests. Poor air circulation and ventilation create unhealthy plants and also provide the perfect breeding ground for bugs. You should place fans near your plants that are plagued by, or susceptible to pests, and in many cases you will experience immediate relief by doing this.


Greenhouse with Open VentsBy choosing the proper fans, vents and other accessories in your greenhouse, you can help eliminate the abovementioned problems and ensure that you have beautiful, thriving plants and crops all year long! Here are some suggestions to get you started:

Exhaust fans:

These fans are highly recommended, as they will decrease the overall temperature of your greenhouse and improve the general health of your plants. They should be placed near the roof and on the opposite side from the door. This way, the cross-ventilation will cause fresh air to come in through the front and stale air to be pushed out through the exhaust fan. Some models of greenhouses may not permit an exhaust fan and if this is the case for you, be sure to make up for it with plenty of circulation fans.

Circulation fans:

Greenhouse Exhaust FanThese fans are essential for healthy plant growth and promote uniform temperature throughout your greenhouse. For most greenhouses, these fans should be placed diagonally on opposite corners, but not too close to the ends and sides. You want your setup to create a circular pattern of air movement.


Depending on the greenhouse you have, you may already have vents on the base or roof. If so, you should always have them open during warm weather for proper ventilation. You should have additional vents placed around the base of your greenhouse, as well as one larger vent on the roof if your greenhouse has the ability to add these on. Cross-ventilation will cause the cool air to enter towards the bottom, flow across your plants and eventually escape through the roof vent.

Solar Vent Openers:

These are extremely useful in addition to having vents in your greenhouse because they will automatically open them when the weather gets warm and close them again when it cools down. Take the guesswork and worry out of managing your greenhouse when you’re not there.

Evaporative Cooling Systems:

An evaporative cooling system can be a great accessory to have, especially if you live in an area that gets particularly hot during the day. These also help to relieve plant stress, promoting their overall health.

Have you experienced greenhouse problems in the past that you solved by supplying better cooling and ventilation? Can you think of any additional issues that poor ventilation can cause?

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