Greenhouses have to be designed to not merely capture solar technology but also adequately Greenhouse Auto Vent ventilate excess heat if temperatures get too hot.
You should always make sure you have adequate vents in the roof of your greenhouse as heat rises and you want that heat to flee.
Greenhouse roof vents work really well as they are located where hot air gathers naturally at the peak of the roof.
If vents in the roof are not possible, make sure to at least have a window to two you can open.
Ideally you would like to have cross ventilation so two windows upon two sides of the greenhouse work best.
However you shouldn’t leave the vents or 
windows open at nighttime as you’ll lose any kind of heat gain and cool your greenhouse an excessive amount of.
Which means you close the vents or windows at night and what occurs another morning: you forget! Right now your greenhouse overheats and if you’re unlucky, you lose some plants.
Or you forget to close the vents at nighttime and your vegetation suffer if the night is too cool.