HIGH HUMIDITY effects

if exhausting / air exchange cannot keep up with humidity, or simply high RH% outside too, you'd need a dehumidifier to reduce it. It will impact transpiration, which will impact how fast it drinks, which impacts how much it grows. -- short answer, yes it will prolly slow it down relative to whatever "optimal" is... does not mean it will stagnate completely.. i've grown plenty of plants in suboptimal conditions, lol. a VPD chart would informa bit how far off the environment is (when the chart references temp, it is the temp at top of leaves.. this will vary from the area's overall temp) The bigger problem is microbial growth. This environment is rife with opportunities for mold and other things we cannot see but will definitely rain on your parade in short order. you are aware, but it is a very serious issue.. you may get lucky but eventually you will toss out a portion of a crop... any large loss over 3-4mos. is not small potatoes. reduced productivity in a notiecable way over time.