The plants are grown in my basement. I had them covered with a clear dome at first, but took it off at least three weeks ago. I have many other sundews there too, like D. regia, D. binata (multifida extrema), wide leaf D. capensis and they all have plenty of dew. I only monitor humidity in my tank setups. I'm not really sure what the humidity is in the basement as a whole? I do have many things down there over wintering. My guess would be 40 to maybe 50 percent? I will have to check. The tanks run much higher like the high 80's for humidity. Oh and I grow everything under T-5 florescent lights. I have fans in all my tanks and three just in the basement for good air circulation. I'm sure there are a lot of people with better ways of growing them, but this has worked for me with the tuberous stuff for like 4 or 5 years now. Like a lot of stuff though you have to respect there dormancy! As I am writing this, my basement temp is 44 degrees. A bit chilly but heck it's only 8 outside.