Growing Nepenthes is very enjoyable, but can also bring its own challenges. Most growers can agree that there is a learning curve with growing and caring for Nepenthes. Nepenthes (Tropical Pitcher plant) leaves are green and waxy, but can turn yellow or even brown due to a list of different reasons. In this post, you will find the most common reasons why your Nepenthes and its leaves are turning yellow and what to do to stop the yellowing of the leaves.
The main causes of Nepenthes (Tropical Pitcher plant) and its leaves turning yellow are too much light, heat stress, low humidity. Other reasons include under or overwatering, using the wrong soil, lack of temperature gradients, lack of repotting/nutrients, aging.
Reason 1: Too much light
If your Nepenthes is getting too much light, its leaves can start turning yellow. In general, Nepenthes need lots of bright light in order to grow and produce pitchers. In the wild, there are two types of Nepenthes – Highland and Lowland ones. Highland Nepenthes grow at very high elevations and get lots of light (sometimes diffused). Lowland Nepenthes grow at elevations lower than 3000 ft (914 meters).
Lowland Nepenthes require higher temperatures and bright, but somewhat diffused light. But Highland Nepenthes require lots of bright light. However, be careful – Highland Nepenthes don’t like temperatures that are too high. If the sun is too hot and bright, you might need to use a shade cloth or a net to diffuse it a little. Humidity should also be high to help plants stay cool.
So if your Nepenthes’ leaves are turning yellow, it could be because of too much light. Try moving or covering your Nepenthes from the light a little, especially if it’s a Highland type. But be careful not to block too much light, because Nepenthes still need lots of it to grow and form pitchers properly. Experiment with lighting and possibly location a few weeks at a time, and you will see how your Nepenthes reacts.
If you previously had your Nepenthes outdoors with grow lights and took it out, it might be suffering from heat stress. This will often be true even if you place your Nepenthes in a shady spot (which you should do initially to help it adapt slowly). Never take your Nepenthes from indoors and place in a sunny spot straight away.
The thing is, grow lights are never as strong as natural sunlight, even in the shade. Sudden change in amount/strength of light can cause heat stress and yellowing in your Nepenthes. Cover your Nepenthes with a shade cloth to avoid heat stress.
Reason 2: Heat stress and lack of day/night gradient
Tightly connected to the first reason of too much light, heat stress is another cause of yellowing in Nepenthes. Very high temperatures and little to no proper airflow will lead to heat stress in Nepenthes. This can exhibit in leaves and even pitchers turning yellow.
Highland Nepenthes, for example, need cooler temperatures than Lowland ones. Highland Nepenthes can suffer from heat stress easily, especially coupled with low humidity/lack of watering. In their natural habitat, higher humidity helps them stay cool. That’s why it’s always recommended to grow Nepenthes types that suit your climate better. If you are really keen to grow specific species, make sure to provide them with an optimal environment.
Besides optimal temperatures, Nepenthes also need temperature gradients during the day and night. This means that temperatures must not stay the same during the day and night. Temperatures for Nepenthes must be higher during the day, and cool at night. That’s mainly true for Highland species, which grow at high elevations and experience temperature drops at night. Highland tropical pitcher plants need warm days/cool nights, while Lowland types – hot days/warm nights without big temperature spikes.
Highland Nepenthes need temperatures of 75-78.8 Fahrenheit (24-26 degrees Celsius) during the day, and around 53-61 F (12-16 degrees Celsius) at night. In winter, temperatures of 55-71 Fahrenheit (13-22 Celsius) during the day and 45-61 F (7-16 degrees Celsius) at night will be optimal. In the wild, Nepenthes grow all year round, but in cultivation, cold winters often make them go dormant. But if you are growing them indoors, they can keep growing all the time.
For Lowland Nepenthes, temperatures of 82-95 degrees Fahrenheit (28-35 Celsius) during the day, and 64-75 Fahrenheit (18-24 Celsius) at night are optimal. In winter, 64-70 Fahrenheit (18-21 Celsius) during the day, and 64-70 Fahrenheit (18-21 Celsius) at night will suffice. Many growers that live in colder climates opt for Highland species, because they tolerate lower temperatures.
So, depending on the type of your Tropical Pitcher plant, make sure to protect them from heat stress. If you notice the yellowing of your Nepenthes, check if temperatures are too high for it. Growing indoors or moving the plant indoors or into a greenhouse in winter is a good option if you experience cold winters.
Reason 3: Overwatering
Most carnivorous plants love their soil very wet and even waterlogged at all times, but not Nepenthes. While Nepenthes love their soil to be wet all the time, they also hate waterlogging. Overwatering can easily cause the yellowing of leaves and pitchers in Nepenthes.
This might sound confusing, and beginners especially might find it hard to know when and how much water to give their Nepenthes. But don’t worry – water only when soil is starting to lose wetness. Make sure the soil is constantly damp, but not overly wet and dripping. This way, your Nepenthes will always be watered, but not overwatered. Water from above.
There is no specific schedule on how often to water Nepenthes, but it will mainly depend on temperatures and light, as well as the pot, and season. The best pots for Nepenthes are plastic pots, glazed ceramic, wooden boxes and orchid baskets like this. Choose a minimum 6-inch (15 cm) wide pot for your mature Nepenthes, and 4-5 inch (10-13 cm) wide pot for young plants.
What is more, your Nepenthes also love high humidity levels. This is especially true for Highland species. Make sure to keep them at around 65-85%. You can even allow them to go as high as 90-100% for short periods of time for Highland species.
Increase humidity by spraying your Nepenthes once a day or even twice a day when it’s hot. Avoid getting water inside the pitchers though. You should mist pitchers (especially growing ones) to improve growth, but without pouring water inside. Having said that, most Nepenthes can adapt to lower humidity as long as temperature, water and light are sufficient.
Reason 4: Underwatering
Underwatering can seriously affect Nepenthes, just like overwatering. Nepenthes love being wet all the time, but not waterlogged. If you wait for your Nepenthes to dry out before you water it again, it might be causing the yellowing of the plant. Make sure to grow Nepenthes in pots with drainage holes and a saucer on the bottom. Throw away excess water from the saucer, leaving only a few millimeters of water.
Nepenthes, as mentioned above, love being wet all the time, but never soggy. So, you must grow your Nepenthes in soil that drains well, but also retains moisture. If the soil doesn’t retain moisture, your Nepenthes won’t have enough water at all times. You can make your own soil mixture by combining light and airy components, such as 50/50 perlite/orchid bark + sphagnum moss like this. 1:1:1 mixture of orchid park, perlite and sphagnum moss is also a great option.
Reason 5: Low humidity
Nepenthes require high levels of humidity to thrive and grow. Of course, the soil in which they grow has to be always wet, increasing overall humidity. But the air humidity is also important. Misting Tropical pitcher plants will help them to stay cool and improve the growth of pitchers. One of the main signs that your Nepenthes is not getting enough humidity is the lack of new pitchers being produced. Or, Nepenthes producing very small pitchers that don’t grow well or too slowly.
Lowland Nepenthes especially love high humidity, and humidity helps these plants stay cool in hot weather. Highland species can tolerate higher humidity levels, but can also adapt to lower levels. However, in general, if your Nepenthes (even if it’s Highland type) has large pitchers, it often will need high humidity levels.
During the growth season, mist your Nepenthes 1-2 times a day to increase humidity levels. You can even use automated misters. Aim for humidity levels between 60-85% and over. At night, humidity levels can reach even up to 90% for some time. After spikes like this, you can let them drop to as low as 40-50% for short periods of time (for Highlanders). Make sure to measure humidity levels with a simple hygrometer like this.
Reason 6: Wrong soil mix
As mentioned above, Nepenthes require a low-nutrient, acidic, and light/airy mix to thrive. If the soil is too alkaline, retains too much or doesn’t hold enough moisture, your Nepenthes will slowly decline. With some potting mixes, your Nepenthes can be fine for a while, and then start declining, leaving you questioning the care.
The best potting soil mixture for Nepenthes is 50/50 perlite/orchid bark and sphagnum moss like this. 1:1:1 mixture of orchid park, perlite and sphagnum moss is also great. Avoid using lava rock, hydroponic or baked clay, or alkaline soil-loving plant mixes to grow your Nepenthes. If your potting mix contains any of those, make sure to make/get a new mix and repot your Nepenthes as soon as possible. Yellowing, blackening and dying of Nepenthes due to wrong soil mix is very common.
Reason 7: Diseases and pests
Yellowing of the leaves or other alarming signs in Nepenthes can also be caused by diseases and pests. In general, Nepenthes are hardy, but they can get attacked by pests or diseases when weakened. For example, softening, brown or black spots might mean that your Nepenthes is suffering from a fungal infection or rotting.
Make sure that there’s adequate air exchange where you keep your Nepenthes. If you keep your Nepenthes indoors on a windowsill, make sure to open windows. In greenhouses and terrariums, also make sure to allow optimal air exchange. You can even use a small fan from time to time if the air exchange is below adequate.
Aphids, mealybugs, thrips and scale are common pests that can attack Tropical Pitcher plants too. Aphids are yellowish/black bugs that are the size of small spots. Thrips are also small – in the larvae stage, they are pale, but when in adult form – they are blackish in color and have wings with hairs. Mealybugs are sap-feeding bugs, that are white and cottony-looking. Scale bugs are bumpy & brownish in color.
All the pests feed on plants’ sap or juices, making Nepenthes vulnerable and weak. Make sure to examine your plant’s leaves, pitchers, stems, and roots. If you see any pests, make sure to prune affected leaves and use some insecticides. Great natural insecticides include neem oil (the main working component is azadirachtin), horticultural oil and insecticidal soap like this. Insecticidal soaps contain fatty acids that will paralyze and destroy soft-bodied insects.
If you suspect any fungus on your Nepenthes, make sure to prune affected parts (disinfect pruners with rubbing alcohol too), repot the plant and use fungicides. Then, look for the root cause – is it ventilation, low light, waterlogged soil, constant extremely high humidity?
Reason 8: Aging
Yellowing of leaves on Nepenthes is not always something care or disease related. As leaves on Nepenthes age, they turn yellow and shrink. And this is normal. If your Nepenthes has lots of new green leaves, and some are turning yellow and becoming dry, it’s fine. Same with Nepenthes pitchers – they have a lifespan that ranges from between a few weeks to a few months. Old pitchers dry out, and are replaced with new ones.
Aging leaves will be replaced by new green leaves. However, if new leaves are turning brown and shrinking at the growth points, it might be related to unfavorable conditions or errors in care.
Reason 9 and 10: Root-bound plant/lack of repotting & lack of nutrients
Other reasons why leaves on your Nepenthes might be turning yellow are the lack of repotting/the plant being root-bound. As your Nepenthes ages, you need to look into repotting it to avoid it becoming root-bound. You should also repot your Nepenthes from time to time because the soil will no longer provide basic necessary nutrients to the plant. This is separate from fertilization, repotting is important no matter if you fertilize the plant.
In general, you should repot Nepenthes every 1-2 years. But if your Nepenthes is large, you need to check if it’s root-bound. Your Nepenthes will be root bound if its roots are circled around the rootball or are coming out of drainage holes. If you allow your Nepenthes to get too large and avoid repotting, it might start becoming weak. Pitcher production will also be hindered.
If your Nepenthes gets very large, it will need more feeding/fertilization to help get essential nutrients. So, if it doesn’t get enough food, you might need to feed your Nepenthes or look into fertilization. If you are sure that your Nepenthes isn’t catching enough bugs, you can feed it crickets, blood worms, grasshoppers etc.
But if feeding bugs isn’t an option, you can fertilize your Nepenthes instead to provide extra nutrients. But in general, if your Nepenthes has got very big, you need to look into separating the plant into different pots.
Thank you for reading this post on Nepenthes turning yellow! If you would like to learn more about growing & caring for Nepenthes, please see this page.