Greenhouses have to be designed to not merely capture solar technology but also adequately ventilate excess heat if temps get too hot.
You should always make sure you have adequate vents in the roof of your 
Greenhouse Auto Vent Greenhouse as heat rises and you want that heat to flee.
Greenhouse roof vents work really well because they are located where heat gathers naturally at the peak of the roof.
If vents in the roof aren’t possible, be sure to at least have a home window 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 should not leave the vents or windows open at nighttime as you’ll lose any heat gain and cool your greenhouse too much.
So you close the vents or windows during the night and what happens the next 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 plant life suffer if the night time is too cool.