Greenhouses are designed to create a controlled environment for plant growth, offering protection from extreme weather, pests, and inconsistent conditions. But one common question for growers—especially in hot regions—is: Do greenhouses keep plants cool in summer?
The short answer is not automatically. In fact, without proper design and management, a greenhouse can easily trap excess heat, causing plant stress, reduced yields, and even crop failure. In this article, we’ll explore why this happens and how to keep your greenhouse cool and productive during the hottest months of the year.
Greenhouses work by allowing sunlight to pass through transparent materials like polycarbonate, polyethylene film, or glass. The interior surfaces absorb this energy and release heat, which gets trapped inside due to limited air exchange—this is known as the greenhouse effect.
While this process is great for warming plants in winter, it can quickly lead to overheating during summer unless countermeasures are taken.
A greenhouse naturally accumulates heat, so without ventilation or cooling systems, internal temperatures can exceed outdoor conditions.
High internal temperatures during summer can lead to:
Heat stress: Wilting, leaf burn, flower drop
Increased water demand: Faster evaporation and transpiration
Growth inhibition: Photosynthesis slows down above 35°C (95°F)
Crop failure: In extreme cases, especially for temperature-sensitive plants like lettuce, tomatoes, or orchids
Understanding these risks helps growers prioritize summer cooling strategies to maintain an optimal temperature range of 18–30°C (64–86°F).
The simplest and most cost-effective method is to increase airflow:
Roof vents: Let hot air escape naturally
Side vents or roll-up walls: Draw in cooler air
Cross-ventilation: Promotes a continuous air exchange
For best results, vents should cover at least 20–25% of the floor area.
Shading reduces incoming solar radiation:
Shade cloth (30%–70% density depending on crop)
Internal shade screens: Retractable or fixed
Paint-on whitewash: Reflects sunlight from glass or polycarbonate surfaces
This can lower internal temperatures by up to 10°C (18°F).
This system works by drawing warm air through wet pads, where water evaporation absorbs heat and cools the air:
Ideal for dry, arid climates
Can reduce temperatures by 10–15°C
Often used in commercial greenhouses
These spray ultra-fine water droplets into the air:
Enhance humidity and reduce leaf temperature
Prevent heat stress during peak hours
Must be carefully managed to avoid excessive humidity and disease
While commonly used in winter, thermal screens also help during summer by:
Reflecting light
Preventing heat accumulation
Reducing energy use for cooling systems
When building or upgrading a greenhouse for a hot environment, consider:
High roof designs: Allow hot air to rise above plant level
Open gable structures: Improve passive airflow
Double-layer poly film with inflation: Improves insulation and reduces external heat impact
Use of light-diffusing materials: Reduce hot spots and distribute light evenly
A well-designed greenhouse combines passive and active cooling strategies for best results.
Modern greenhouses use automation and sensors to manage internal conditions:
Temperature sensors
Humidity and CO₂ controls
Smart fans and exhaust systems
Automated shade and mist systems
Systems like Priva, Argus, or Netafim integrate multiple environmental factors for efficient operation, especially in large-scale commercial greenhouses.
A commercial grower in Malaysia installed:
High-roof polycarbonate structure
Roof and side ventilation with insect nets
50% internal shading system
Pad-and-fan evaporative cooling
Result: Summer temperature reduced by 12°C, stable humidity maintained at 60–70%, and yields increased by 20% compared to the previous season.
So, do greenhouses keep plants cool in summer?
Not by default. Greenhouses amplify heat. But with thoughtful design, proper materials, and active cooling systems, you can keep your plants thriving even in the hottest months.
Investing in smart cooling solutions not only protects your crops but also increases yields, extends growing seasons, and boosts your ROI.
As a professional agricultural greenhouse manufacturer, we specialize in custom greenhouse solutions for hot climates. From small-scale farms to commercial agri-businesses, we help you build structures that work with the climate—not against it.
Contact us today to get a cooling-optimized greenhouse quote tailored to your region and crops.
+86 189 2488 9901 +86 189 2455 5194
+86 189 2488 9901 +86 189 2455 5194
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