I grow my highlanders outside. They experience lows in the 40's-50's during winter / summer nights to highs in the 70's-80's to low 90's on occasion during the days. Although highlanders don't seem to like temperatures in the 90's, they can tolerate them in short intervals provided there's ample humidity. I've had them go 4 to 5 days in the 90's in full sun without any problem. I do keep my juvenile Nepenthes under shade cloth to avoid pitcher loss and leaf burn. Although they are under shade cloth, all my Nepenthes experience some direct sunlight. Direct sunlight can create red spots and / or leaves to yellow a bit. This is normal and is not a problem. Sometimes new arrivals experience too much direct sunlight and leaves will bleach out. That's a sign that I need to move the plant to a shadier location until it adapts to outdoor conditions. Usually this isn't a problem with terrarium grown plants under grow lights. However, it can be with windowsill specimens. If leaves bleach out, then moving your plants slightly away from direct window sunlight into more diffused lighting should solve the problem. I will also grow my extra small highland Nepenthes as windowsill plants until they get around 4" or so and can be moved outdoors. Smaller Nepenthes less than 3" in diameter can be more susceptible to loss from outdoor cultivation. Growing highlanders in lowland conditions where temperatures stay in the upper 60's to low 70's at night is an area I have no expertise. I have spoken to other growers that have tried growing highlanders in lowland temperatures and they report that the plants stop growing and eventually die with long exposure to the warm temperatures. However, there are some growers in Hawaii that report success with highlanders grown under warmer conditions that one wouldn't expect. But that's generally the exception than the rule.

Intermediates are easier for me to grow than lowlanders but can also be a bit tricky. Most intermediate hybrids will tolerate my winters into the mid 40's to low 50's without damage. They do slow down until the weather warms up. It also helps if the days are warm. A warm day can offset a cold night without too much ill-effect. But in December and January when nights stay in the upper 30's to low 40's and the days in the upper 50's to low 60's my intermediates will stress. Growth ceases and leaf edges will brown. Many times the growth tip will stop growing all together. Then when spring comes the new growth tip emerges from the old one. Low temperatures in hybrids reflect the female parentage more than the male. When I see intermediate hybrids listed as intermediates, I look to see what the female parent is and that helps me determine if I can grow it on the cooler side. Intermediates make good choices for growing indoors as houseplants or "windowsill" Nepenthes. They don't need the hot humid temperatures of a lowlander or the night time temperature drops of highlanders. Many Exotica Plants intermediate hybrids make excellent choices to experiment with indoors.

When it comes to lowlanders, they just don't do well as houseplants. Some tolerate windowsills when small and will pitcher for a while. But as they get larger, they need the warm, humid temperatures for proper pitchering. Nepenthes like N. bicalcarata and N. ampullaria will hang in there when small but eventually stop pitchering and look awful. Thick leaved lowlanders like N. truncata and N. clipeata can adapt to growing as houseplants but do much better as typical lowlanders. Hybrid lowlanders where one of the parents is an intermediate could do well as an indoor Nepenthes given the other needs are met. It just comes down to experimentation with the lowlanders indoors. I've tried a lot of them without much success. So if you're thinking about growing on windowsills or as houseplants, stay away from the lowlanders.