Humidity gets to 90% at night, any help?

Gettin really damp at night here, so I made a little greenhouse but im not sure if its going to help. Any input would be appreciated.

90% how exactly? start growing mushrooms lol really dont know what to say man other than dehumidifier or ac with dehumidifier but im sure that not the cheap way to fix it.

Im really close to the beach, just checked 40 minutes ago and outside rh was 90%

wow I actually feel dumb my humidity out side is like 86% I guess 90 not that high my house stays close to 40-50% cause of ac so it just seemed high to some one who was HIGH but again im still not much help sorry

Just checked inside the greenhouse and its 97% at 54 degrees

get a box fan or something cheap and blow air in constantly on ground level and have another tall oscillating fan blowing on the plants gently back and forth through the night! should keep mold or mildew from growing because of the constant air flow...

So if inside the greenhouse is 95% and outside is 90% I guess my best option is to use the greenhouse a a roof only?