Question
Hey Guys,

Until just a few moments ago, I was using two 150W CFLs along with a 15W and 20W tube for my terrarium, which is an old 30 gallon fish tank.  However, I measured the temperature in there and it was 90F around the taller plants!  Too hot for highlanders.  So, I took off the CFL's, and this is will be my setup without them:
2x 20W
2x 15W
Fluorescent tubes

The problem is that the lights are around 17" above most of the plants.  In your eBook, you suggest around 8 inches.

Any input?

 Thanks!
Andrew

Answer
Hi Andrew,

First, if you've managed to find a 150W compact fluorescent bulb, you could possibly use that instead of the tubes.  (I'm assuming that the 150 watts are actual output and not equivalent output.)  This bulb would be more than ample to provide the necessary light intensity for your Nepenthes.  (I'm also assuming you're growing only Nepenthes.)

Many highland Nepenthes will tolerate temperatures into the lower 90s, so the temperature in your terrarium isn't much of an issue.  It's the nighttime temperature that is most critical for highland species.  In the tropical rain forest of Southeast Asia, plants will typically experience temperatures in the 80s and 90s, even at high elevations (up to 6000 feet).  It's the nighttime temperatures that differentiate highland from lowland.

Our Nepenthes greenhouse typically gets into the lower 90s during the summer, but it also experiences temperatures as low as 42癋 at night.  Our highland plants seem to love this type of temperature swing.

Of course there are some highland Nepenthes that prefer slightly cooler daytime temperatures.  These are the ultra highlanders, such as N. rajah and N. villosa.  They usually occur above the 6,000-foot elevation.  But since you mentioned tall plants, I assume you're not growing these species.  (This is where it would be helpful to know the species you're growing and your location so I could give you more specific recommendations.  Otherwise, I can only give general information.)

So I would actually go back to the 150-watt fluorescent bulb. You'll have better growth and pitcher development.  You also won't need the other two tubes since their output would be dwarfed by the larger bulb.

If you still prefer to use the tubes rather than the bulb, elevate the smaller plants so that they are closer to the light.  Again, I'm assuming that you have your plants in individual pots.  If your plants are in a natural-style terrarium, then you'll need to consider redoing the terrarium so the plants are in individual pots or switching back to the compact fluorescent bulb.

Good growing!
Jacob Farin