Nepenthes (Tropical Pitcher Plant, Monkey Cup Plant)

How to grow Nepenthes (Tropical Pitcher Plant)?

Nepenthes is a tropical, semi-climbing carnivorous plant belonging to the genus Nepenthaceae. Generally,  they find their ideal habitat among the rainforests and montane forests of the Malay Archipelago, Borneo, New Guinea, Indonesia, the Philippines, and Western Australia, where they grow by using the tendril that connects the leaf to the ascidium to “cling” to the surrounding vegetation and grow taller (some can reach up to 15 meters in height). Some species can also be seen in Madagascar, Sri Lanka, and parts of India and China.

What type of sunlight is best for the growth and health of Nepenthes (tropical pitcher plants)?

Nepenthes is a carnivorous plant that tolerates little direct sun, especially during the hottest hours of the day.

Why do they avoid direct sunlight?

Because in the wild, they live within rainforests where the sun is masked and the sunlight is filtered by taller plants.

So where should I place my Nepenthes?

For all Nepenthes, it is ideal to place them in a shady area (porch, under large trees, etc.) or by using shade cloths. If the humidity is high enough, direct sun in the early morning hours or the late afternoon hours will not be a problem.

How to water tropical pitcher plants?

Nepenthes poorly tolerates waterlogging, so you should keep the soil moist at all times but never soggy with water.

In summer, when temperatures are extreme, you can leave 1-2 cm of water in the saucer until it is absorbed. This is because evaporation is usually fast enough to prevent any stagnation.

Use only distilled water. Alternatively, all waters that have an extremely low mineral salt content are suitable. For example, all condensation water (air conditioner, dehumidifier) conductivity of the water should have a value of fewer than 50 microsiemens.

Why should stagnant water be avoided?

In their habitat, the soil is very draining, so water percolates downward. For this reason, it is extremely rare for there to be water stagnation.
In response, stagnation would cause a lack of oxygen in the soil; this condition results in root asphyxia, and as a result, the delicate roots of Nepenthes would rot irreparably.

Why use distilled water?

There are several reasons, but let’s try to think in terms of the environment.
What does it mean to grow Nepenthes in an extremely rainy environment on draining soil of a mostly inert nature?

Simply put, the mineral salts and most of the nutrients in the soil are constantly washed away by rain, which by its nature does not contain minerals. For this simple reason, the root system of Nepenthes has adapted to receive very few nutrients from the soil.

An essential point for good results is to ensure high air humidity because, as mentioned above, Nepenthes grows in rain-fed environments where rain is very frequent and, therefore, humidity is very high.
A lack of humidity would damage the leaves irreparably.
However, good air recirculation is required to avoid fungal diseases that may arise in high-humidity situations.

How can I solve this problem?

Let’s not panic because there are many solutions! Let’s start with the assumption that many of the easiest Nepenthes to grow make do with a generous sprinkling of distilled water 2-3 times a day all over the plant. If you decide to grow indoors, such as in a semi-enclosed terrarium, the problem is practically solved from the start because the relative humidity of the air inside a terrarium is sufficient, though it is still a good idea to spray the leaves frequently.

Alternatively, many growers use misting or fogging systems (i.e., recreating fog with more or less inexpensive tools), especially inside large terrariums, grow rooms, or greenhouses.

The use of misting systems is very useful when growing highland Nepenthes because these systems help to bring down temperatures, avoiding too high temperatures during the day and at dusk by also helping to create the necessary temperature change. (Note: these systems alone help but do not guarantee ideal conditions; for best results, fans, extractors, water cooling systems, air conditioners, etc. are usually used.)

Which substrate should I use for Nepenthes (Tropical Pitcher Plant, Monkey Cup Plant)?

While 50% peat and 50% perlite is fine as a general substrate, and consequently even for Nepenthes it creates no problems, many growers use mixtures in various proportions of peat, perlite, bark, akadama, and dry or live sphagnum.

In my experience, a mixture of 60 percent perlite and 40 percent peat, with the addition of live or rehydrated sphagnum moss to wrap the roots and give a little extra moisture, turns out to be a good compromise for beginners struggling to find certain materials.
Personally, I have had the best results by mixing rehydrated dry sphagnum moss and perlite in equal proportions and always adding live sphagnum moss around the base of the plant.

CAUTION: Do not breathe in unprotected perlite dust; moisturize it properly before handling it; it is very fine dust and harmful to our lungs!

Why such light soils?

Because Nepenthes needs moisture, it also needs very aerated soils to avoid root rot problems. Consequently, it is good that the soil does not have too much peat or material that can “pack down.” It is therefore preferable to increase the proportion of perlite or possibly add other materials that are always inert with a thick and suitable grain size so that the roots can “pack up” while still remaining well aerated. In addition, it is essential that the substrate be free of nutrients, as in the long run, they would be detrimental to Nepenthes, which, although more tolerant than other carnivorous plants, may no longer develop ascidia and in the long run would inexorably lead to the death of the plant.

Can I fertilize my Nepenthes?

It is always a good idea to avoid fertilizing all carnivorous plants, including Nepenthes.
However, it is possible from time to time to fertilize Nepenthes (this genus of the carnivorous plant only) with very dilute doses of orchid fertilizer or any generic foliar nutrient, as long as you follow three rules:

• dilute the fertilizer to a third or fourth share
• Spray the product only on the leaves.
• Give the product 10 to 15 days apart.

How to care for Nepenthes in winter?

Nepenthes do not go into dormancy! Because they are tropical plants, they can vegetate all year, but only under constant conditions.

Solutions to ensure more or less constant conditions all year round are different depending on the type of habitat they belong to, i.e., whether Nepenthes is lowland, intermediate, or highland.

To solve this problem, it is necessary to ensure dry soil and relatively low air humidity.

Let us try to clarify this in more detail.

• Lowland: Ideally, you should have a terrarium or grow box with stable conditions all winter, as many of these Nepenthes (especially the ultra-lowland ones, i.e., the most “delicate” ones) begin to show signs of suffering already around 18–20 °C. However, it is possible to “overwinter” them indoors as long as they are placed in a well-lit room where temperatures are not prohibitive for them or in a double window under the same conditions.
• Intermediates and Highlands: Because they require lower temperatures than lowlands, they are well adapted to spend the winter inside a double window or even in a terrarium or grow box as long as temperature changes are kept to a minimum and temperatures do not fall below 15 °C.

If you decide to make the indoor-outdoor move, i.e., grow Nepenthes outside in summer and inside in winter, it is important to move the plants at the time most suitable for them. That is, when outdoor temperatures (especially night temperatures) are balanced with indoor temperatures so as to avoid overstressing the plant.