To keep a greenhouse cool during hot weather,focus on strategies that promote airflow,reduce direct sunlight,and manage humidity without compromising plant health.Here are some effective methods based on common recommendations:
1.Improve Ventilation
Open vents,doors,and windows to allow hot air to escape and cooler air to enter,ideally creating cross-breezes.Automatic vent openers can help if you’re not around to monitor temperatures.For better circulation,install exhaust fans to pull out stagnant hot air.
2.Use Shade Cloth or Netting
Install shade cloth(at least 40-50%density)over the roof or exterior to block intense sunlight while still allowing light for photosynthesis.Position it slightly above the structure to prevent heat buildup,and remove it during cooler periods.
3.Incorporate Evaporative Cooling
Set up evaporative coolers(like swamp coolers)or misting systems to lower temperatures through water evaporation,which can drop the interior by 10-20°F in dry climates.Ensure good drainage to avoid excess humidity that could promote mold.
4.Plant Strategically for Natural Shade
Grow large-leaved or vining plants(e.g.,grapes or tomatoes)inside or outside the greenhouse to provide natural shading and transpiration cooling.This also helps maintain a balanced ecosystem.
5.Other Tips
Monitor and automate:Use thermometers,hygrometers,and timers for fans or misters to keep temperatures below 85°F(29°C).
Whitewash or paint:Apply temporary white shading paint to the glass or plastic exterior to reflect heat.
Avoid overcrowding:Space plants to allow air movement and reduce heat retention.
These approaches work best in combination,tailored to your climate and greenhouse size.If temperatures consistently exceed safe levels for your plants,consider consulting local extension services for region-specific advice.
