Is it possible or recommended to grow nepenthes outside of terrariums? Aren't nepenthes tropical plants needing constant high humidity?
Nepenthes can be grown as windowsill plants as long as adequate conditions are provided.
There are two main divisions for nepenthes, highland and lowland with some groups in between. Lowlanders tend to need high temperatures and very high humidity (imagine a rain forest). Highlanders need lower temperatures and usually do not require as much humidity (think tropical mountainside). Highland and intermediate nepenthes are usually the best candidates for windowsill growing. I have grown one of mine (N. maxima) in a south-facing window for several months now, and it has been consistently producing pitchers.
Here are a few tips for growing without a terrarium:
- Keep the medium moist - it doesn't have to be visibly wet all the time, but it should be moist to the touch.
- Make sure the plant isn't getting Sunburnt - If parts of the leaves are dying you might consider reducing the amount of light it gets. This can also occur if you neglect to water the plant for a day or too.
- Make sure the plant is pitchering - the presence of pitchers on a plant usually indicated the health of the plant. If it is not producing any, the plant might be unhappy with its conditions.
- Spray it occasionally - Spraying nepenthes with a $1 spray bottle can help water the plant and gives it a little humidity boost.
- Make sure your conditions are not too hot - If the area where your nepenthes is growing gets over 90° F during the day, the plant will not do very well, especially when growing pure highland species (not hybrids).
- Water with distilled, RO or rain water if needed - If your tap water is hard, you will need to use an alternative water source. RO (Reverse Osmosis) water is the best option if you have a filter, otherwise use rainwater or distilled. When using rainwater you should make sure the rain isn't polluted (acid rain etc.)
Some good candidates for windowsill growing for nepenthes are:
N. Ventricosa, Maxima, Alata, Ventrata (Ventricosa x Alata), 'Miranda'.
Nepenthes hybrids tend to be more hardy and able to withstand windowsill conditions.