Plants with Attitude
An approach to growing highland Nepenthes in almost any climate:  basement cultivation.
Cultivating Nepenthes is a fun and rewarding hobby, enabling the grower to observe the development of some of the most beautiful and bizarre plants on earth.  Moreover, with the advent of tissue culturing techniques in recent years, plants hitherto all but unavailable may be had for as little as one hundred dollars.  However, given the rarity of these plants, responsible growers must ensure that they can provide conditions appropriate for their new aquisitions.  Since most highland Nepenthes require warm days, with good light and temperatures ranging from 25 to 30 degrees C, and cool nights down to 10 C with attendant high humidity, it is apparent that their cultivation presents a special set of challenges for those not fortunate enough to live in the appropriate climate.
Cool Conditions
Living in a rather arid, and for most of the year, relatively cold part of the United States, several years ago we decided to try to find a way to grow these plants that would allow us to emulate their moist, montane conditions.  Since summers throughout most of North America are too hot for all but the most adaptable highland Nepenthes, it was immediately apparent to us that the only way to provide a consistently cool environment, short of having massive electrical bills, was to grow the plants in a basement room.  A reasonably deep basement will usually offer ambient temperatures much cooler than 30 C, even on the hottest days, with even cooler night temperatures.  Moreover, plants grown in such a location are not subject to untimely death in the event of a sudden power failure, as they might be in a conventional, air-conditioned greenhouse in midsummer.

However, having selected a basement room as a location for Nepenthes cultivation, lighting and humidification needs must also be addressed.  The former may be readily accomplished by means of a variety of electric lamps.  Initially, we grew many of our plants under broad spectrum fluorescent lamps, with excellent results.  The only drawback to the use of these lamps is their relatively short lifespan of approximately six months, and the fact that plants must generally be located fairly close to the lamps to receive adequate illumination.  This latter matter can prove troublesome as plants grow larger, and does tend to interfere with one's observation and enjoyment.

metal halide lamp Lighting
So, after speaking with several other growers, we decided to obtain a metal halide lamp and fixture.  Although the initial cost of such a system is high, (presently about $350) this is somewhat offset by the fact that a single 1000 W lamp can adequately illuminate an area of about 2.5 m x 3 m, at a distance of at least 1 m.  In addition, lamp life is typically about one year.  Furthermore, one can obtain lamps specially formulated for plant growth, which ensure good results.  Drawbacks to such a system are few, but among them is the fact that a 1000 W lamp does take a fair amount of power to run 13 to 14 hours per day.  We figure that our system costs us around $1 per day when set for a 13 hour photoperiod.  In addition to the cost of electricity, such lamps do generate a lot of heat.  This can be a boon since this will tend to warm one's plants during the day, helping to simulate their natural habitat.  However, one must remain aware of the fact that, unless shielded, the lamp can explode if it comes in contact with water, with disastrous results.  In addition, if hung close to any flammable items, the lamp can start a fire, or damage items with a low melting point.  In the final analysis, though, if one wishes to grow a number of Nepenthes, and is circumspect in one's placement of the lamp, such a system is an excellent choice.
Fig. 1  Metal halide lamp
humidifier Humidification
However, for those of us living in an arid climate, there also remains the matter of humidification.  Humidification can be accomplished several ways, since there are a variety of humidifers and foggers now on the market.  Having tried a variety of these, we can state with some conviction that, for a sizeable growing area, a good choice is an ultrasonic humidifier.  These devices use high frequency sound to break water up into microscopic droplets, thereby creating a virtual fog and enabling one to put a considerable amount of water vapor into the air rather quickly.  There are three major caveats associated with this choice, however, which we feel compelled to point out.  First of all, these devices require freqent cleaning (approximately weekly) to prevent buildup of potentially harmful microorganisms in the water reservoir.  Secondly, one must use a reasonably pure source of water, or may have to contend with a fine white "dust", which arises from the evaporated minerals naturally occuring in most tapwater, and which is not good for the lungs.  This problem may be circumvented by the use of distilled water, or by means of water purified by a commercially available RO (reverse osmosis) unit, which is what we use.  Finally, of course, one must fill up the unit regularly, a routine which can become tedious after awhile.
 
 
Fig. 2  Ultrasonic humidifier
Partitioning
The matter of humidification is not the end of our concerns, though, for it is generally necessary to restrict the humidified air to the growing area, both to ensure adequate humidification, and to prevent rot in other parts of one's home.  It is here that one can get a bit creative.  To solve this problem we constructed a simple rectangular frame.  The frame is made from standard 1 inch diameter PVC pipe.  This material was chosen for several reasons:  It is cheap, lightweight, durable, strong, easy to cut and work with, and most importantly, it will not rot!  It is then a simple matter to construct such a frame and set it up at the desired location.  We recommend that the pieces of the frame be fitted together (rather than glued) since one will surely need to take it apart at some point, and the joints, if hammered together, are not likely to break apart.

Finally, one must cover the frame, and an obvious choice is some sort of plastic.  We recommend 6 mil poly; it is durable, and will permit the transmission of light.  However, be sure that the poly covering used is UV resistant.  The lamp will give off enough UV radiation to degrade the plastic, and in a year or two, one will likely find oneself recovering the chamber or, at the very least, repairing a number of tears in the covering.  On the other hand, if one wishes to maximize reflection inside the chamber, mylar may be a better choice.

Keep in mind that it is not a good idea to have the lamp inside the chamber.  The humidity will promote rust, and may, as mentioned earlier, cause the lamp to shatter.  Therefore, it is necessary to make sure that there is enough room between the top of the chamber and one's ceiling to hang the lamp.  In addition, it is necessary to construct a window, larger than the lamp housing, in the chamber top to allow light from the lamp to enter.  For this purpose we chose a thermally resistant transparent plastic, which we put into a frame.  This was then set on top of the chamber, over a region devoid of the plastic covering to maximize light entering the chamber (and avoid the obvious risk of fire).  Allow at least 6 inches between the frame and the lamp -- more if you fear that the proximity of your lamp to your window is hazardous.  We urge caution in the interest of reader safety, but also wish to point out that we have had such a chamber running for several years now without any problems at all.
Details, details
Once all is in place, photoperiod may be simulated by means of a typical appliance timer used to control the lamp.  We usually leave the humidifier on continuously, having found that it typically needs to be filled only once each day.  Heat from the lamp will increase the capacity of air within the chamber to hold water, thereby reducing the relative humidity during the day, and allowing it to rise during the night.  This variation seems to be beneficial to our plants; overnight they experience a kind of "fog", which burns off after the "sun" is up.

Furnishings for the growing chamber are a matter of personal taste.  For our needs, we elected to constuct simple benches, with tops made from cedar, which is rot resistant.  Casters have been installed at the ends of the legs to allow easy movement of the benches within the growing chamber.  Beautiful they are not, but they serve our purposes nicely.  In addition to keeping plants on benches, it is also possible to install shelves, or run steel pipes through holes drilled in the frame to provide a support for hanging plants.

To cool down the enclosure at night, one may use a fan to draw in cool air from outside, possibly routing the fan to ductwork allowing it to draw in air outside the basement.  During the summer months, an airconditioner may be used, a technique which we have employed during the past year.  This has allowed us to reduce overnight lows to about 15 C, even during the hottest months of the year.

Since implementing such a growing environment, we have enjoyed a substantial degree of success cultivating a number of Nepenthes commonly considered challenging, as well as many other plants with similar environmental needs, such as various species of Heliamphora, Drosera regia, and so forth.  We do not believe that we would have enjoyed such success otherwise.  In fact, at least three local growers have constucted similar chambers for their plants at the time of this writing, and we believe that all of them have been pleased with the results they have obtained.  In closing, it is our hope that these simple guidelines will serve to help a number of other people to successfully grow these fascinating plants.