It is "essential" to ventilate greenhouses in the daytime in order to maintain a constant temperature, it has been suggested.
Tom Larson, writing for gardening publication Grit, explains that the different conditions between day and night require careful management.
"When I leave my plants in the greenhouse at night, a small thermostatically controlled electric heater keeps the temperature above 50 degrees F," he states.
"During the day, heat is always a hazard so ventilation is essential."
Mr Larson now has a heat-sensitive window opener to allow air into his greenhouse should he forget to open the door himself.
This, he adds, was inspired by the occasion on which he closed the door and returned to find his plants beyond revival.
He recently observed in the publication that windows beneath an overhang typically receive less light as the sun rises higher in the sky.
But by installing a shelf, plants may be elevated to keep them in the sun for longer.