About bottom heat
Sometime ago, maybe a year or so?, I decided that the heating mat I had on my petiolaris terrarium was just not enough to produce the temperatures I wanted for the plants I had in there. I already had the first mat stuck onto the back of the tank and so I chose to put the new one on the bottom. Now, I have had some experience with sundews and bottom heat and it wasn't a good experience. The plants stopped producing dew and when I was convinced the heat coming from underneath was the problem I terminated the experiment and the plants recovered. My solution was to try to insulate the watering trays for the Petiolaris sundews from the heat by sitting them on reflective bubble-type insulation. Long story shortened: my plants began a long downslide and additions I made to the collection at that time never grew normally, some never even producing complete traps.
Recently, after trying everything else I could think of, I removed the mat from the bottom and put it on the front of the tank. I was desperate enough to do this finally! Guess what? The plants are back on the upswing and species that have never done well for me are putting out new growth. Some are even producing the first dewy traps they have ever had for me. I expect the improvements to continue.
Moral of the story? While I can't say across the board that bottom heating sundews will bring disaster I can say that it can in at least some circumstances. If you are using a heat mat to heat a tank I would recommend that you do it from the side, despite it looking kind of funky. Bottom heat can sometimes, for some plants, bring more rapid rooting of cuttings so I don't mean to say it is to be avoided in all cases.
If things continue to improve I will consider my plants to be photogenic before too long. In this case I will post photos here in celebration. Thank you for reading this. For those of you who also grow plants from this group I wish you success! There are still too few of us.