How to regulate temperature and humidity?
White Widow is a strain that can well tolerate higher temperatures, but it won't react so well when exposed to too cold temperatures. Even when plants are exposed to temperatures over 27 ºC, White Widow can continue its normal function. But it won't do so well if you overexpose to say 13 °C. The optimal temperatures for outdoor White Widow plants are above 21 ºC throughout the day and above 16 ºC at night. Indoors, you can go as high as 30 °C, given that you supplement your room with a carbon dioxide enrichment.
As per humidity, during germination, stick at around 70%. During vegetation, drop to 65%. Once you reach flowering, start reducing humidity by up to 5% on a weekly basis until you reach a point of 35% humidity.