Drosera, commonly known as the Sundew plant, is a carnivorous plant that comes in at least 194 species. These alien-looking plants lure and capture insects using a sticky substance secreted by specialized glands that cover the leaf’s surface. Any insects they catch supplement the poor mineral nutrition found in the soil in their native environment, including bogs.
Caring for any sundew can be tricky and might leave owners asking the question; why are my sundew’s leaves turning brown? Sundew leaves may turn brown when they are brought into the house for the first time, and the change of light intensity plus the heat in their environment is too much for the plant to handle.
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Although the amount of light and heat a sundew receives can cause the leaves to turn brown, this piece will examine other reasons and diverse ways to keep this from happening.
Too Much Light and Heat Outdoors Can Turn the Leaves of a Sundew Brown
Sundew plants love to grow outside, where they have plenty of chances to capture and digest a variety of insects. However, sundews are vulnerable to overheating and do not like direct, hot sunlight.
There are three precautions a sundew plant’s owner can take to prevent their leaves turning brown, including:
- Grow the plant in the shade or,
- Move the sundew to a partly shaded location
In removing the overage of heat and light, the sundew should bounce back, and although the leaves that have turned brown have died, others will soon spring up in their place.
Browning Caused by Too Much Light and Heat When Bringing the Plants Inside
Some people choose to bring their sundew plants inside when the weather turns cold, especially in climates where the temperature outside can reach below zero.
However, the sudden changes in humidity, temperature, and light may turn the leaves of a sundew plant brown.
Too little humidity, very warm temperatures, or too much or little light causes the plants to become stressed, and this stress can lead to permanent damage to the plant or even its death.
Steps to Take to Prevent Browning Damage to a Sundew Plant
For both problems having the plants outdoors and bringing them in, there are some steps that can be taken to ensure the plant’s leaves do not turn brown and die. These include when the plant:
- Needs to acclimate to lower humidity
- Needs to acclimate to brighter light
- Needs to acclimate to warmer temperatures
Acclimating a sundew plant involves the gradual adjustment of the plant to new conditions. Also known as hardening, following a few tips can save a sundew from burning.
Acclimating to Lower Humidity
When purchasing a sundew plant, before taking them out of the plastic cube, gradually expose the sundew to the lower humidity of the inside of a home. This allows it to become used to the difference from the store to home.
If the plant is being brought inside in the fall for the winter, the plant will need to adjust to the much lower humidity inside as compared to that outside the home.
Acclimating to Brighter Light
Because the sundew plant’s leaves are sensitive to bright light, if the leaves of the plant are turning brown, they may be burning from the direct light while sitting in an inside windowsill.
To prevent this from happening, grow the plant outdoors in a shady location for a week or two to make certain the plant can adjust to a change of light outdoors first.
Next, move the sundew plant to a partly sunny location for several weeks until it has colored up and appears established.
Then, be observant of how the plant adjusts. If the plant took to the shady location okay but appears not doing well in the partly sunny one, consider moving it back to allow it to acclimate for a longer period. If the sundew is stressed the second time, then consider keeping it in the shade inside your home.
Acclimating to Warmer Temperatures
Allowing a sundew to adjust to the heat either inside or outside the home is critical to its leaves remaining healthy. The technique for relocating a plant from a cooler environment to a warmer one involves several steps.
The first step is to move the plant to its new location and leave them there for half an hour. If the plant is doing well, leave it there for an hour.
Next, take the plant back and allow them to recover. The next day, place the plant in its unfamiliar environment for two hours or until the leaves begin to show stress. Afterward, return the plant, and the next day repeat the previous step.
Gradually increase the plant’s time in their new environment until they can be left there safely the entire day.
Sundew plants will be more stressed outdoors than in because of air conditioning, but after acclimating, the leaves will not turn brown.
Finding Your Hardiness Zone to Prevent Leaf Browning on a Sundew
Sundews originated from warm climates of the world, including South Africa, South America, and Australia where frost is rare, and it never snows. Sundew’s preferred area to grow is open, wet fields in poor soil where there is lots of sunlight.
Knowing the hardiness zone of the area of the home where the owner of the sundew plant lives can make the difference in successfully raising them or having them turn brown and die.
In 2012, the United States Department of Agriculture (USDA) published a plant hardiness zone map that helps plant growers determine which plants will thrive in the area where they live. The different zones on the map are called hardiness zones, and knowing the area a sundew plant’s owner lives can determine whether their plants can live outdoors. (Source: USDA.gov)
Sundews are highly adaptable, so growing them indoors on a nice sunny windowsill is an option if the zone the owner lives in is too cold. If, however, the owner lives in a region where the temperature rarely drops below 55 F than the plant will grow well outdoors.
Using Artificial Light to Prevent Leaf Browning
Although too much sunlight causes the leaves to turn brown on a sundew plant, having too little or the wrong light can also do considerable damage.
The type of bulb matters when it comes to keeping a sundew plant healthy. Using a simple shop light over the plants is an easy fix, however, it is vital to keep in mind that light intensity and duration are important considerations. The common white fluorescent light placed 6” above the sundew plant run on a timer for 14 hours a day is a great basic set up for the sundew plant.
In fact, the longer light period offered by using a timer helps mimic the light the plant would receive were it outdoors. On average, they receive 16 hours of sunlight in summer, 14 hours in fall plus spring, and 12 hours in the winter.
Do not use a green bulb as the sundew plant absorbs every color but green, and it will die.
Browning of the Leaves Part of The Dormancy of a Sundew
Sundews, like many other carnivorous plants, require a dormancy period that generally occurs in winter. During this time, the leaves may appear brown, but the plant is not dying. It is hibernating.
For three to four months in winter, cooler temperatures and shorter daylight hours trigger the dormancy period to begin, and the leaves will drop off the plant and stop growing altogether. This is totally normal and should raise no alarm.
It is during this time of dormancy that sundews growing in artificial light may need to be removed into a darker area of the home to help them achieve a successful hibernation.