well atm its no Problem because you dont have flowers, But 90 percent is alot....
And it wont be better by itself, Because Plants get bigger, and transpirate more.
rh rises....
I dontknowwhereyour Plants are.. but heatin the area( if its autumn at your Place) helps,,,
// getting a dehumifidier would be next step
Iam having that Problem in summer, .... I bought asmall infrared creamic heater with thermostat
and warmed upthe tent... Rh lowered to 50/55 percent---and plants floweredwithout mold