High humidity when the light is off?!

Look up a VPD chart pal

Are you running an extraction fan or just an internal one? An extraction fan would solve the excess humidity problem. If you have a humidifier, switching it off at night would be my first idea, as cannabis does not really need extra humidity (at all), and certainly not at night. After looking through your diary, I would suggest that you don't stop the grow nutrients too early, you really shouldn't start with the bloom nutrients until the flowers have formed small "tufts" of pistils or "budlets". Certainly don't begin with just bloom nutrients when there are only preflowers/primordia on the stems, as your plant still needs adequate nitrogen in early flower. It is only third/half way through flowering that nitrogen requirements really drop off. Hope this helps, Organoman.

70% is good at that temperature in veg - fits nicely into the VPD chart. When the lights go off and temp drops RH naturally increases, if you ha e a humidifier you can set it at say 60% and it will peak at 70 at lights out or get a dehumidifier - with humidifiers make sure you have an automatic or you can almost make it rain in a tent or turn it into the desert in a matter of hours.

Some strains are more resistant to high humidity that others. If you are growing a strain that is vulnerable to bud mold from high humidity then a dehumidifier should be considered. The reason for your rise in humidity at night could be from your A/C not running asuch at night due to the drop in temp outside. Central air conditioning in most houses will naturally dehumidify the air in the building. So running less at night could be the reason for the rise in humidity. Hope this helps! ✌️

Hi there,RH 70% is still not a problem at this stage of growing.But you don't want to get higher than 60% in the flowering stage otherwise there will be chance of mold.Here's a link for relation between temp and RH to check whether the plants are in comfort zone.Good luck and happy growing. .. ✌️ https://www.420magazine.com/community/threads/vpd-charts.490676/