Hi fellow lowland Nep Growers,
I don't want to rain on anyone's parade here concerning growing highland Nepenthes in lowland conditions, but maybe a few words of caution (negative) could be made into a positive thing.
I have been growing Nepenthes for over ten years now, and my wife Michelle and I maintain a moderately large collection in a greenhouse here in Boca Raton, Florida. Our summers, mid May until mid October, are truly lowland tropical conditions, with night temperatures barely dipping below 78 degrees F for three months straight. Day temps are regularly up into the high nineties (sorry for the F. instead of C., but its what I'm accustomed to using). The greenhouse is covered in a poly material that reflects heat, so during a hot summer day, it is cooler than the outside. The problem is really achieving a night temperature drop for the highland plants. Our summer nights are very humid, typically 80 percent or more, so evaporative cooling is not very efficient. We don't have swamp coolers or other systems because the best they can do on a summer night is get temps down to about 70 F, sometimes in the wee hours of pre-dawn-maybe even 68 degrees. This is not a sufficient enough drop for most highlanders.
We have tried a number of different highlanders, and while still small, immature plants, they are more tolerant of heat. They grow happily at the three to six inch size. As they grow up, about two years later, they start to show signs of stress, and eventually die from heat exhaustion. The climate in Queensland (Exotica Plants)is tropical, but closer to a southern California type of environment than south Florida or Singapore. They experience naturally lower night temperatures during the summer, coupled with lower humidity. This allows evaporative cooling to work better, and the Mansell's do use a swamp cooler in the main greenhouse, giving them appropriate night temperature drops for highland Nepenthes.
If you live in a climate with warm, humid nights the best way to get an appropriate night temp drop is air conditioning or refrigeration. Yikes! There goes the electric bill!
The next best alternative is a totally enclosed greenhouse using a combination of swamp cooler pads and misting system, with fans pulling the air the length of the greenhouse. Intermediate conditions can be achieved, and one Florida grower I know was successful with N. faizaliana, fusca, highland veitchii, all kinds of ventricosas, maxima, even spathulata. However, rajah barely held on and never really put on a show of pitchers we would want to see.
What is interesting is how highland hybrids may be adaptable to lowland conditions: the term "hybrid vigor" really applies to Nepenthes. The other alternative is to seek out clones from the lower altitude limit of a species. You folks in K.L. have the lowland form of N. sanguinea (Antarabangsa hills) very close. I don't think this plant is even in the US., and really should be put into tissue culture. I have heard rumor of a lowland form of ramispina for years, but have yet to actually see it or really verify its existence.
Again, my purpose is not to discourage, but to encourage other growers in warm regions to investigate alternate methods of achieving what conditions these plants need.
Happy growing, and keep us informed with what happens.
Boca Raton, Florida