Question

Tropical Terrarium   Hi Guys! Hope you are great! I have a really important question to ask. I am new at growing Nepenthes. Soon when you do the update on cobraplant.com Im going to order Drosera Adelae, Drosera Multifida Extrema, Nepenthes Chanianna x Veitichi, maybe Nepenthes Singalana x Aristochloide, Utricularia Long., Sarracenia Purpurea Venossa and some Mexican Butterworts. Is Air Circulation really important for Nepenthes ? Cause I have to thrive them in a pot in a terrarium because of the humidity. Because without the terrarium is 40%-50% but inside the terrarium at day is at 70% and at night 80% with the lid completely cover on the terrarium. How can I raise the humidity with the lid off ?

With the Butterworts I was wondering how much humidity do butterworts need? Im afraid to let them rot.

This is the terrarium I am using

Hope you can help me with this :/ Thanks!

Answer

Nepenthes sanguinea in   You indicated that your ambient humidity outside of the terrarium is 40-50%.  Believe it or not, this is actually very acceptable for many tropical carnivorous plants.  If you visit our website, you'll see that we are strong advocates of NOT using terrariums.  They are expensive, difficult to maintain, and sometimes causes more problems than solutions.  

Carnivorous plants are plants, first and foremost.  While many come from tropical regions, they acclimate very well to most household conditions.  I grow Nepenthes in my windowsill in my home in Oregon.  We sometimes reach 20% humidity in summer, yet the plants continue to produce very nice pitchers. I also grow Mexican butterworts in my windowsill.  They produce very nice leaves despite our humidity dropping below 50%.  

Lighting, not humidity, is the most important factor when it comes to growing carnivorous plants.  As long as you maintain proper soil moisture, humidity will take care of itself.  Your household humidity is perfectly fine to grow carnivorous plants, or any tropical plant for that matter.

So carnivorous plants will acclimate to lower humidity if you give them the chance to do so.  Air circulation is also very important.  Without it, you put the plants at risk for fungus and mold.  Another issue is your plants outgrowing the terrarium.  Nepenthes can get quite large.  Are you willing to increase the size of your terrarium and increase the light output?  If not, then you have to figure out how to acclimate your plants to lower humidity.  It won't happen right way, but you should have a plan when your plants outgrow the terrarium.  

I know this might not be the response you were expecting.  We're strong advocates of growing tropical carnivorous plants as regular houseplants, especially if you happen to live in a region where humidity is already acceptable for growing tropical plants.  You don't need very high humidity unless you're trying to grow very prized specimens for shows.  Even then, the plants will go into shock when you remove them from the terrarium to present at the show!

So I encourage you to reconsider using a terrarium.  Some people want to grow plants in a terrarium because they enjoy the aesthetics.  However, that is very different from thinking that carnivorous plants need constant high humidity.  This is a myth that we have disproved countless times at our nursery.  

Visit our photo gallery for photos of our plants growing in lower humidity.
http://www.cobraplant.com/photogallery/humidity

Good growing!
Jacob Farin