Greenhouses have to be designed to not merely capture solar energy but also adequately ventilate extra heat if temperatures get too hot.
You should always make sure you have sufficient vents in the roof of your greenhouse as heat rises and you want that heat to escape.
Greenhouse roof vents function Greenhouse Auto Vent really well as they are located where heat gathers naturally at the peak of the roof.
If vents in the roof aren’t possible, ensure that you at least have a screen to two you can open.
Ideally you would like to have cross ventilation therefore two windows on two sides of the greenhouse work best.
However you shouldn’t leave the vents or windows open at nighttime as you’ll lose any heat gain and cool your greenhouse an excessive amount of.
And that means you close the vents or windows during the night and what happens another morning: you forget! At this point your greenhouse overheats and if you’re unlucky, you lose some plants.
Or you forget to close the vents at nighttime as well as your vegetation suffer if the night is too cool.