Greenhouse Weather Station Control Systems
What’s happening outside your greenhouse should decide what your vents and curtains do next. Here’s how a weather station makes that automatic.
What Are Greenhouse Weather Stations & Why You Need One
aYou must have a weather station, whatever automation solution you use for your grow system. Weather stations gather data about the environment outside your greenhouse — temperature, humidity, sunlight levels, rain, and wind — using sensors running both inside and outside the structure.
Install your external weather station somewhere visible, and clean it regularly to keep readings accurate, especially in areas prone to bird activity or leaf fall. Your data is only as good as your sensors, so invest in a system built to hold up. A controller like the KVT-400 pairs a weather station with a touchscreen interface so you’re reading and acting on the same data in one place.
Roof Vents Explained
Roof vents are a passive cooling technology that uses hot air convection. They’re one of the most efficient ways to cool a structure, particularly in temperate climates — hot air rises to the top of the greenhouse and exits through the vent, pulling in cool air from below.
Open-roof construction is adjustable: opening the vent keeps the greenhouse cool, closing it retains heat.
Open roof vents come in open-panel, retractable-film, flat-roof, or low-profile styles. Bringing in cooler outside air during hot weather is cost-effective and has helped many growers reduce production time and improve plant quality. Mesh screens around exposed areas keep pests out, though depending on the screen type this can reduce air movement by up to 45%.
Side Vents Explained
Side vents protect your plants while increasing ventilation. If your plants sit on a bench, rolling up the side walls to bench height lets cold air flow underneath — creating good growing conditions while reducing reliance on fans and electricity.
Research (Santorini 2005, Wang 1999) points to a combination of roof and side vents as the most effective layout, particularly in warmer areas at low altitudes. If your setup relies on manual adjustment, our manual controls are built for exactly this kind of side-vent operation; if you’d rather it run itself based on conditions, that’s what the weather station and automated curtain motors handle together.
Natural Ventilation vs. Wind-Driven Ventilation
Natural (Buoyancy-Driven) Ventilation
Natural ventilation relies on the temperature difference between the inside and outside of the greenhouse to create a buoyancy force that drives airflow — warm air is less dense than cold air and rises, creating an upward stream similar to a chimney. It works without wind and can run on hot summer days, and offers steadier airflow than wind-driven ventilation. The tradeoff: it depends on the temperature difference, and the greenhouse’s design affects how well it works.
Wind-Driven Ventilation
Wind blowing outside the greenhouse creates a small pressure difference between the windward and sheltered sides, moving air toward the sheltered side. It works best when vents are angled to take advantage of prevailing winds, though the effect is minimal if side walls aren’t paired with roof vents, and depends on the length and size of the greenhouse.
Greenhouse Vent Details
How to Size Roof and Side Vents
Per the American Society of Agricultural and Biological Engineers, the roof vent area should roughly match the total sidewall vent area, and each should be at least 15–20% of the floor surface. Getting this ratio wrong is one of the most common reasons a naturally-vented greenhouse underperforms — see our full ventilation system design guide for sizing worksheets and layout examples.
Where Greenhouse Vents Should Be Placed
Roof vents are typically hinged on both sides of the ridge. Side vents are most often installed at bench height, where they do the most good for plants sitting on benches.
Why Greenhouse Height Matters
Taller greenhouses are easier to ventilate because of the greater buoyancy effect and the extra room hot air has to rise above the plants before it needs to exit. If your greenhouse sits in a hot, humid climate, you may need additional ventilation control equipment beyond passive vents — talk to AutoVent about what that looks like for your structure.
Talk to AutoVent About Your Greenhouse
It's crucial to note that if your greenhouse is in a hot and humid climate, you may need to consider additional ventilation control equipment. Contact AutoVent today if you're ready to start talking about ventilation controller solutions for your greenhouse.