Troubleshooting a Pitcherless Nepenthes

Jacob here with Sarracenia Northwest. Over the years, we’ve answered thousands of questions from carnivorous plant growers. One of the most common questions we get is why their Nepenthes isn’t producing pitchers. There are many factors that affect pitcher development, so in this video I’m going to share with you the thought process I go through when helping other growers.

Now, when someone comes to me for help with their pitcherless Nepenthes, it’s usually a plant that they bought at a local nursery or garden show. We even carry them on our website. These Nepenthes are suitable for first-time growers and easy to grow as houseplants. Typically, they’ll show me a photo of their plant with lots of new growth, but no new pitchers. When I’m helping out a grower, I look at 6 key growing aspects to pinpoint where the problem could be. The first three are the most common ones I see.

SUNLIGHT
The first thing I assess is lighting. Pitchers are intricate leaf structures, and Nepenthes need a lot of energy to produce them. A pitcher has many parts, such as the lid, peristome, and wings. Pitchers also contain glands that secrete fluids and enzymes to capture and digest insects.

Producing pitchers is energy-intensive, and Nepenthes get their energy from a process called photosynthesis. This process requires sunlight. However, a lot of first-time growers underestimate the amount of sunlight Nepenthes need. If a plant doesn’t get enough sunlight, it won’t have enough energy to produce pitchers. So inadequate sunlight is the most common reason for lack of pitchers.

One of the signs of insufficient sunlight is large, dark green leaves. Leaves are green because of a pigment called chlorophyll, which plants use for photosynthesis. When lighting is inadequate, a plant will try to maximize energy production by growing larger leaves and producing more chlorophyll, causing the leaves to appear dark green. But if a plant is struggling to maximize photosynthesis, it’s going to focus on surviving rather than thriving. So, in low light conditions, Nepenthes will have lots of dark green leaves, but no pitchers.

When a Nepenthes is getting adequate sunlight, its leaves are often bright green, depending on the variety. Some will have a bronze tinge. Others will be red. Others will be even darker. The different colors appear because the plant is getting enough sunlight for photosynthesis.  So, it can produce other pigments that have other functions for optimal plant health.

How much sun do Nepenthes need? They thrive in partial sunlight, which means about 4-6 hours of direct sunlight and bright indirect light during the rest of the day. Check your plant—does it really get 4-6 hours of direct, unobstructed sunlight every day? If the leaves are large and dark green, and your plant has no pitchers, the lighting is insufficient. 

Even if you think your plant is getting enough sunlight, what you think is irrelevant. Nepenthes are plants, and they don’t care what you think. They are and will always be the ultimate judge of what is bright enough. When growers move their plants to a sunnier spot, they often see new pitchers forming within 4 to 8 weeks.

You can also add LED lights to supplement natural sunlight if your windowsill isn’t getting enough sun. Your basic cool-white shoplights are usually enough to do the job.

Sometimes growers will back off on lighting because the sun can be too intense. But that’s usually because of temperature rather than the light itself, which brings us to the next factor - temperature.

TEMPERATURE
Temperature is important because a plant’s metabolism is temperature-dependent. If it’s not warm enough, a plant’s metabolism might be too slow to produce pitchers. The indoor temperature should be at least 70°F during the day. The ideal temperature range is between 78° and 82°. At night, a temperature drop to 65° is enough for most plants.

One of the common signs of low temperature is older leaves turning yellow. There are other reasons why leaves turn yellow, and I’ll talk about them later. But at the start of winter, we often hear from growers wondering why their older leaves are suddenly turning yellow. When the temperature drops, metabolism slows down. With a slower metabolism, a plant will struggle to maintain all of its leaves. So it will shut down the older ones to prioritize the new growth. However, the new growth will also grow slower than usual. 

Nepenthes can also stop producing pitchers if the temperature is too hot. Pitchers form on tendrils located right at the tip of a leaf. These developing tendrils are very delicate and vulnerable to heat damage. When that happens, the tendril will stop growing and you won’t see any pitchers.

So, check your temperatures. Are they in the ideal range? If the windowsill is too cold or too hot, consider moving your plant to a new location. Once the temperature is corrected, plants will start producing pitchers within 4-8 weeks.

AIR DRAFTS
The third thing I check is air drafts. Is the plant next to a vent blowing hot air or cold air? Nepenthes appreciate good air circulation, but it doesn’t like hot or cold air blowing on it. When air from a vent blows on a Nepenthes, the plant may stop producing pitchers because it’s struggling to regulate metabolism and moisture loss. So, if your Nepenthes is near an air vent, move it to a more sheltered location.

These three factors – lighting, temperature, and air draft – are the most common reasons for poor pitcher development. I also make sure these factors are properly addressed before I consider other factors. If a plant is struggling because of poor sunlight, improper temperatures, or being near an air vent, addressing anything else will have limited results. So, I always assess these three factors first before moving on.

ROOT HEALTH
The next factor is root health, which can impact the overall health of a plant. If the roots are unhealthy, the plant can’t absorb enough water from the soil. When this happens, the plant will stop pitcher growth and survive only with leaves. A Nepenthes needs a healthy root system to thrive and produce pitchers. There are five common factors that influence root health.

ROOT HEALTH: WRONG SOIL
The first is using the wrong medium or soil ingredients. If the medium is rich in nutrients and fertilizer, roots may burn and die. The growing medium should be very low in nutrients and slightly acidic. For this reason, avoid using potting soil, garden soil, or forest compost. We recommend using equal parts dried sphagnum moss and perlite. This mix works well with a wide range of Nepenthes and is much more forgiving than other mixes. Make sure the ingredients are properly hydrated and thoroughly mixed before potting your Nepenthes.

Some growers skip the perlite and use only dried sphagnum moss to grow their Nepenthes. We don’t recommend this because the moss often compacts over time. When it compacts, it will stay wet longer and prevent oxygen from reaching the roots. This can lead to root rot. With root rot, you might notice the older leaves turning yellow all at once. The plant will also have very few pitchers, if any. I made a video about this topic. You can find the link to that video down below.

To prevent soil compaction, use a coarse aggregate, such as perlite. Perlite doesn’t compact, so it will assist with drainage and root aeration. You can also use small pumice if you can’t find perlite. However, avoid using orchid bark. Orchid bark breaks down over time. When it does, the medium will compact. Orchid bark is also expensive. As long as you use enough perlite or pumice, you’re good to go.

ROOT HEALTH: OVERWATERING
The media should also be damp but not waterlogged. Unlike tropical sundews and other carnivorous plants that like to sit in water, Nepenthes prefer moderately moist soil. If the plant is constantly sitting in water, root rot can occur.  The symptoms of overwatering will look identical to media compaction – many older leaves turning yellow. The only difference is that the media might be suitable for Nepenthes, but the pot is sitting in water.

The best way to water Nepenthes is to water from the top and let the water drain completely, just like you would for a regular houseplant. Top watering does two things. First, it flushes out nutrients that naturally build up in the medium. Second, it pulls oxygen to the roots and prevents root rot . Water again when the top of the soil begins to lose moisture.

ROOTH HEALTH: ROOTBOUND
Sometimes a Nepenthes will grow well for a couple of years and then suddenly the soil is drying out more frequently, and the older leaves are turning yellow. The new growth might also be smaller than normal. If you’re needing to water more often and the older leaves are turning yellow, the plant might be rootbound. You can determine if a plant is rootbound by simply flipping it over and removing the pot. You’ll see a thick layer of black roots encircling the medium.

When the roots overgrow like that, water has a hard time seeping to all parts of the medium. Instead, most of the water will flow to the sides of the pot, leaving the inner section dry. This is why the soil seems to dry out more frequently. Over time, the plant finds it difficult to pull enough water up to the leaves despite having lots of roots. That's why the older leaves turn yellow. The new growth might also be smaller than usual because the plant is trying to minimize moisture loss. The only solution is to repot the plant into a larger pot. 

ROOT HEALTH: ROOT DISTURBANCE
This brings us to the next factor affecting root health – root disturbance. Nepenthes don’t tolerate root disturbance very well. When we repot a Nepenthes, we typically keep the root mass intact and transfer it into a larger pot, being careful not to disturb the roots too much. We then fill the empty space with more medium. If we’re successful, the plant won’t miss a beat. It’ll continue to produce more pitchers.

But if you try to remove some of the media and disturb the root mass, your plant will stop producing pitchers for a while because it needs to repair some of the root damage. We often see this happen with large plants. The bigger the plant, the more roots it needs to support its size. Disturbing its root mass too much will slow it down. So, when repotting your plant, try to keep the roots undisturbed whenever possible.

I also don’t recommend cutting off so-called excess roots on Nepenthes. I’ve seen too many growers end up with dead plants because they followed someone’s advice about cutting off excess roots. I don’t endorse that practice at all. Instead, when repotting your plant, keep the root mass intact.

These are the five common factors related to root health. Root health is crucial for pitcher growth because it influences how water moves from the soil to the leaves. If a plant cannot absorb enough water, it won’t have enough for photosynthesis, or maintain leaf moisture, or grow new pitchers. It will sacrifice pitchers to conserve water and survive. A Nepenthes needs a healthy root system to thrive and produce pitchers. 

ACCLIMATION
If all the factors I already mentioned are properly addressed and the plant appears healthy, the next thing I consider is acclimation. Was the plant a recent purchase? Was there a recent change in its environment? Did the grower move the plant to a new spot in the house?

Plants, including Nepenthes, thrive in very stable conditions. If you recently purchased your plant from a nursery, you will need to allow it time to adjust to its new home. This process can take anywhere from several days to several months, depending on the plant.

It also depends on how the plant was purchased. If your plant arrived fully potted in the mail, it will likely adjust very quickly. If your plant was shipped bare root, without soil or a pot, it may take several months to acclimate.

The keyword is patience. Nepenthes grow slower than other houseplants, so give your plant time to adjust. Most of the common varieties of Nepenthes will grow a new leaf every 2 to 4 weeks. Some Nepenthes grow much slower, producing a new leaf every few months, even in ideal conditions.

Another thing I notice people do is chase the sun. This is when growers move their plants from one window to another during the same day to maximize sunlight. They keep their plant in an east window in the morning and then move it to a west window in the afternoon. 

Plants are stationary organisms. They don’t move around like a lizard trying to sun itself. If you keep changing its location, you prevent the plant from acclimating to a single location. Constant changes in temperature, air flow, and lighting mean that your plant may take longer to adjust. You also risk damaging the tendril every time you move it. So, keep your plant in one place. If you’re worried it won’t get enough sun, use supplemental lighting. We have a video about that, and you can find it in the description below.

TENDRIL STIMULATION
I’ll admit that this one is more ambiguous, but it appears to be a significant factor for some Nepenthes. Nepenthes are essentially woody vines with two growth stages: a rosette stage and a vining stage. During the rosette stage, the plant remains compact for a while. The pitchers are also very colorful. As the plant matures, it transitions into the vining stage.

In nature, when a Nepenthes is in the vining stage, the space between leaves gets longer as the plant tries to reach above the tree canopy, where there’s more sunlight. As the vine grows, its tendrils will wrap around other plants to help secure it in place. The pitchers also look different. They’re often paler and more funnel-shaped. These upper pitchers appear different from the lower pitchers because they are designed to catch different types of insects in the tree canopy.

For some varieties of Nepenthes, the tendrils require stimulation, such as touching something they can wrap around. If there isn’t anything for the tendrils to cling to, they won’t elongate or develop into a pitcher. When a plant is in the vining stage, it can sometimes be hard to tell if a lack of tendril stimulation is a problem. If I’m satisfied that all the other factors I discussed are properly addressed, I’d recommend to the grower to use netting or narrow stakes to give something for the tendrils to wrap around. The hanger of a hanging basket is sometimes enough for the plant. You can also group plants together so their tendrils can latch onto other plants. We see this happen a lot in our greenhouse.

Just keep in mind that tendrils are delicate. Don’t wrap them around things yourself. They will find things to wrap around on their own. Just make sure they’re touching something they can wrap around. And don’t attempt to unwrap them, either. You risk damaging the tendril.

So, these are the 6 factors I consider when figuring out why a plant isn’t growing any pitchers – sunlight, temperature, air vents, root health, acclimation, and tendril stimulation. Now, you might notice something missing from this list. Humidity. I didn’t mention humidity because humidity isn’t a driving force for pitcher growth. For most Nepenthes available to the average grower, humidity is a non-issue, just like it is for many common houseplants.

I also discussed humidity in detail in two videos, so I’m not going to cover it here. I recommend watching those videos because I explain the physiological mechanisms of how Nepenthes adapt to fluctuating humidity. If there is one thing I want you to know about humidity, it’s this.

Plants can adapt to fluctuating humidity, but they cannot adapt to improper lighting and temperature. When sunlight and temperature are at ideal levels, and a plant’s roots are healthy, Nepenthes can thrive in regular household humidity and grow beautiful pitchers.

Now, the six factors I covered in this video aren’t the only factors that affect pitcher development, but these are the most common ones growers encounter. So, if these factors are properly addressed, your plant has a good chance of producing pitchers. The important thing is to be patient with your plant and give it time to acclimate to new conditions.

If you want to learn more about our growing recommendations, download our care guide at growcarnivorousplants.com. Since starting our nursery in 1995, we have been dedicated to teaching our customers how to grow their Nepenthes in a sunny windowsill. Since then, we have thousands of customers who successfully grow Nepenthes without the aid of humidifiers, misters, or humidity domes.  

And while you’re on our website, check out the Nepenthes we have in stock. Our inventory changes monthly and seasonally, so be sure to subscribe to our channel for notifications of inventory updates. Thank you for watching. I look forward to seeing you in another video.

• The original question and response have been edited for publication.
• To submit a carnivorous plant question, visit Ask the Growers