The general rule here is a very nutrient poor mix with fantastic drainage properties and preferably made up from products such as perlite, coconut husk/chip, long fiber sphagnum moss, pine bark and sphagnum peat moss. Coconut husk is better if it’s been soaked in rain water for some time prior to using.
The actual mixes are as varied as the plants themselves and a quick internet search will give you recipies from expert growers from around the world.
However, feel free to create your own mix from this list of ingredients to suit your location (depends on whether you have a windowsill collection or a greenhouse plus your low mineral water availability)….Hint: keeping it simple with 2 or 3 ingredients seems to work best with both the plants and the wallet.
The amount of light needed by nepenthes varies greatly from highlanders to lowlanders and their geographic origins. Research the species you have to find information about it’s natural habitat and try to recreate that as closely as you can.
As a general rule, highlanders can handle a brighter light for more of the day, as exposed mountain tops and cliffs…but be careful the pots don’t dry out or that it stresses your plant with the extra heat.
Lowlanders generally prefer more shaded days…like the forrest or jungle habitats where dappled light penetrates the canopy or they get direct light for only a couple of hours a day.
All Nepenthes like a high humidity environment and the most useful information I received when starting out is the hotter the day gets or during the heat spells in summer the more humidity needed. This helps helps to cool the plants and stop pitchers drying out.
Lowlanders require 70% humidity or higher and they like it constant (just like their jungle homes)
Highlanders and hybrids however are more tolerant of fluctuations so will generally thrive above 60% with occasional dips and peaks (like their native mountain top environments).
A lack of developing pitchers is a sign that your plants need more humidity.
All Nepenthes require a very low mineral/salts water.
Rain water, Reverse osmotic water, and distilled water are all preferred, but if you live in an area with water below 250 ppm then this is acceptable as long as you flush their pots with distilled water every couple of weeks to flush out the accumulated salts/nutrients.
Highland species should range between 20-25°C all year round and drop down to 10°C during the night during the winter months. This evening drop is essential for their survival.
However, lowland plants need constant temperatures of 25-30°C during the day and 18-20°C minimum at night all year round.
Hybrids can tolerate a much broader range of temperatures.
You will need to research each of your plants to see where they are most comfortable.