Proper greenhouse ventilation keeps your plants healthy by regulating temperature, reducing humidity, and ensuring fresh air exchange. Whether you're using roof vents, louvres, or fans, airflow is essential to prevent plant stress, disease, and heat buildup—especially during peak growing season. A well-ventilated greenhouse supports stronger, more productive crops year-round.
A well-ventilated greenhouse is the foundation of strong, healthy plants. Whether you're starting seeds, growing food through the seasons, or cultivating specialty crops, airflow plays a critical role in maintaining balanced temperature and humidity. This guide will walk you through the essentials of greenhouse ventilation, from natural and mechanical options to seasonal strategies and smart accessories.
A greenhouse is designed to trap warmth and protect your plants from elements, but all that trapped air can quickly lead to problems if it isn't moving.
With the right setup, your greenhouse stays comfortable and balanced no matter the weather outside.
Natural airflow relies on openings that allow warm air to rise and escape while drawing cooler air in.
Mechanical systems give you more control, especially in larger greenhouses or extreme climates.
Pro Tip: Most growers find a combination of natural and mechanical ventilation works best.
Every greenhouse is different, and your ventilation needs will depend on its size, structure and location. As a general rule, you'll want roof vent openings to equal roughly 15 to 20 percent of your greenhouse's floor area. All BC Greenhouse Builders greenhouses come standard with automatic roof vents, and the number of vents included is scaled to the size of your greenhouse to ensure proper temperature control. These vents are solar-powered, opening and closing automatically based on interior temperature, so you can spend more time tending to your plants and less time adjusting your greenhouse conditions by hand.
For mechanical ventilation, the sizing of your exhaust fans is equally important. A well-sized fan system should be capable of exchanging the entire volume of air in your greenhouse every one to two minutes during hot spells. This keeps interior temperatures stable and prevents heat stress.
Climate also plays a role. In regions with high humidity or intense heat, you may need to increase your airflow capacity beyond standard recommendations. Additional vents, shade cloth, or higher-capacity fans might be necessary to maintain plant health.
Not sure where to start? Out team can help you calculate exactly what your space requires.
Adjusting your ventilation strategy seasonally helps maintain a healthy environment year-round.
Even experienced growers can run into problems. Keep an eye out for these common missteps:
Staying proactive helps you avoid costly mistakes and protects your crops.
At BC Greenhouse Builders, we've spent decades helping gardeners create well-ventilated spaces that grow healthier plants.
Here's how we can support you:
Great ventilation is one of the simplest ways to create a thriving, productive space. Whether you're updating an older greenhouse or planning a new build, a little extra airflow can go a long way.