Houseplants can help you decorate your indoors and create a pleasant, lively atmosphere. However, they sometimes produce unexpected problems that are difficult to deal with, especially if you aren’t very familiar with plants. So what’s causing your houseplant to drip sap, and how can you fix it?
Your houseplant may be dripping sap because of a pest problem, an injury, loose nectar, or guttation. Although loose nectar and guttation are normal, you can reduce the dripping sap and avoid attracting pests by cleaning your plant regularly.
In any case, there are ways to fix this problem and get your houseplant clean and tidy again. In this article, I’ll break down the most common reasons why your houseplant drips sap and tell you how to deal with them.
1. Pests Leave Honeydew Secretions on Houseplants
If you were inspecting your houseplants and you noticed something unusual, such as one of your plants dripping sap (or at least, a liquid that looks like sap), you’re most likely to feel worried.
I hate to break it to you, but you might be dealing with a pest infestation, especially if the dripping liquid is thick and sticky. This funny liquid is called honeydew.
While that’s a rather innocent-sounding name, it’s actually another name for pest poop! But don’t worry, it’s okay to touch it with your bare fingers. It won’t harm you (although you should probably wash your hands).
Now, how did this honeydew end up on your houseplant? And more importantly, where are the pests?
Well, they’re probably hiding under your houseplant’s leaves. Not only are these pests incredibly small and inconspicuous, but they also love to hide under thick foliage, so they aren’t spotted by predators. You’ll have to look closely to spot them, especially if there are still only a few.
The good news is that if you noticed the dripping honeydew before you did the pests, chances are there are only a few of them, which means you’ll have an easier time dealing with the infestation.
These pests—usually scales, aphids, and mealybugs—all have slightly different appearances, but what’s common about them is that they feed on the nutritious sap inside plant leaves.
This sap is loaded with sugars, which is the energy source preferred by plants. However, pests don’t particularly like sugar. They prefer to consume proteins.
Plant sap has little protein, so pests need to consume a lot of sap to get their fill of protein. While doing so, they excrete all the excess sugar as honeydew, which is what you see drip off your houseplant.
Is Honeydew Harmful?
Honeydew is not directly harmful, as it’s just sugary excrement, so it won’t hurt your plant. The problem is that honeydew encourages the growth of sooty mold.
This black fungus resembles soot (hence its name) and feeds on honeydew. Interestingly, it won’t harm your houseplant directly. But it does block off access to sunlight and oxygen, thereby reducing photosynthesis.
Photosynthesis is how a plant converts nutrients into food. A plant already fighting off an attack by pests can’t afford to simultaneously suffer from reducing food production. Also, honeydew attracts insects such as ants, bees, and even lizards, which protect the pests attacking your plants from their natural predators.
So, even though the honeydew won’t hurt your houseplant, it will bring about more problems and worsen existing ones.
How to Fix
Dealing with a pest infestation is relatively straightforward, but it’s a long-term process. You likely won’t be able to wipe out the pests entirely with a single treatment session, so persistence is necessary.
To fix the above problem, you need first to isolate the infected plant and eliminate any and all pests inhabiting the affected houseplant since they’ll keep producing honeydew as long as they’re there.
While treating an infested plant, keeping it isolated from the rest of your indoor collection is important. Pests can spread from plant to plant easily, and we want to prevent this from happening to the best of our ability. Once you’re done, you can clean up any remaining honeydew or mold and have your houseplant look as good as new.
Unfortunately, once a plant is overrun with pests, saving it becomes highly unlikely. A plant overrun with pests is best discarded to prevent the infestation from spreading. However, your houseplant is probably far from that point if you just notice the honeydew for the first time.
Here are some common plant pests and how to remove them:
Remove Scales Manually or Use Insecticides
Scales are tiny insects protected by a chemical-resistant coating. This means light insecticides will be ineffective in treating a scale infestation. They look like brown lumps and are commonly found on the underside of foliage, although you may also spot some on the plant stem.
They move very slowly, to the point where it usually looks like the bumps are stationary, but the good news is that these pests can’t fly.
Since insecticide is ineffective against scales, you’ll have to resort to other means.
Take the following steps to deal with a scale infestation:
- Brush scales off the foliage manually: You can use a toothbrush or a wet cloth for this purpose. Drop the scales into soapy water where they’ll become immobile and eventually die.
- Apply horticultural oil: The powerful surface tension of horticultural oil cuts off oxygen, causing the bugs to suffocate. It’s safe for application on plants, too. Neem oil is an option that works well.
- Use rubbing alcohol: Rubbing alcohol dissolves the protective coatings that scales wear. Once this coating is gone, you can use insecticide effectively.
- Apply insecticidal soap to the plant: Scales without their protective shells will die.
Eliminate Aphids and Prune the Plant
Aphids are tiny winged insects that come in a variety of colors. They’re also vectors for plant diseases, which makes them even more dangerous. They also like to fly around the site of infestation, making them a very bothersome pest.
To deal with aphids:
- Isolate the plant: Flying aphids can easily get about, so isolation is extremely important.
- Use neem oil: The oil will cut off the oxygen and cause any pests that come in contact with it to suffocate. However, it’s best used early on in the infestation.
- Use insecticidal soap: Aphids don’t have protective coatings like scales, so you can use heavy weapons if necessary. It’s usually effective to start with some insecticidal soap.
- Make a dish soap-vinegar trap: This will catch any stragglers. (Dish soap is also one of the main ingredients for killing fungus gnats with a DIY solution.)
- Cut off heavily-infested parts of the plant: If the situation calls for it, you should cut off heavily-infested foliage, as it’s likely beyond saving.
Aphids are notoriously resilient pests. They reproduce like crazy. Just when you think you’re done getting rid of them, they come back.
If the problem just doesn’t seem to go away, read my article on why houseplants keep getting aphids: 6 Reasons Why Your Houseplants Keep Getting Aphids
Identify and Remove Mealybugs
Mealybugs may or may not be winged. A telltale sign of a mealybug infestation is the presence of cotton-like residue on foliage, as mealybugs produce this residue while reproducing. The bugs themselves are usually white in color, and they’re dealt with similarly to aphids.
Clean Up the Honeydew and Sooty Mold
Regardless of which type of pest you’re dealing with, you’ll likely have to treat your houseplant with insecticide several times before the infestation goes away entirely. You’ll see results immediately after the first session, but you’ll also have to take out those that will grow from larvae.
As you treat your houseplant, clean up any honeydew and mold on the foliage. With any luck, the pests will go away, and so will the honeydew.
2. Sap is Released From Injury Sites
Your houseplant may be leaking sap because of an injury. The sap is carried throughout the plant body via the xylem and phloem cells. It’s similar to how blood is transported through our veins.
A cut, laceration, or break in your houseplant can cause the sap to leak and drip out. The point of injury would likely be quite apparent in this case.
Such as injury could be caused by anything, really. Pets, especially cats, often mess around with houseplants and inadvertently hurt them. However, this isn’t aggressive behavior. It’s usually driven by curiosity, boredom, or playfulness.
How to Fix
Sap leakage caused by physical injury to the plant will be minor and self-resolving. You don’t have to do anything. Your plant will close up the wound and heal itself.
However, if you do have a cat that likes to toy with your houseplant, you should discourage them from doing so. Many popular houseplants, such as jade plants and pothos, have foliage toxic to pets, so it’s best to keep them separated.
3. Your Houseplant Has Loose Nectar
Nectar is essentially sugary water—it’s a substance produced naturally by many houseplants. Usually, it’s produced in flowerheads, and its purpose is to attract pollinators.
See, plants, like all living organisms, need to reproduce. They have male reproductive organs and female reproductive organs.
The male parts produce pollen, which needs to come in contact with the eggs inside the female parts for successful fertilization and eventual reproduction to occur. But plants can’t move, so the pollen won’t get there on its own. That’s where pollinators come into play, more specifically, insects like the honeybee.
Plants attract these pollinators by offering them nectar as food. In return, the pollinator transfers pollen to them.
But why is this nectar dripping off of your plant? Nectar usually remains in flower beds, but sometimes, a little extra can drip off. This is likely to happen if the offending houseplant belongs to a species known for producing a lot of nectar when it flowers.
Why Do Some Plants Have Extrafloral Nectaries?
Extrafloral nectaries are nectar-releasing glands that don’t participate in pollination. They aren’t found inside flowerheads like regular nectaries.
If your houseplant has extrafloral nectaries, you’re especially likely to experience some dripping nectar from time to time. If nectar exists only to help carry out pollination, and extrafloral nectaries don’t aid the pollination process, why do extrafloral nectaries exist?
Some scientists think that extrafloral nectaries are a clever defense mechanism. The nectar they release attracts carnivorous insects such as ants and ladybugs for feeding. These insects will only feed on the nectar and not the plant itself, but they will keep at bay the herbivorous insects that are more of a threat to the plant.
You can check out this helpful YouTube for more information:
How to Fix
Excess nectar isn’t going to cause any problems beyond making your plants feel sticky. However, it may cause you some inconvenience if it drops onto furniture or the floor.
Out in the wild, excess nectar would attract ants, but your houseplant’s nectar probably won’t since it’s potted and kept in a domestic environment.
It’s safe to leave the nectar be, but you can clean it up with a wet cloth if you wish. Plants produce the most nectar during the flowering season, which is in spring. Nectar production will go down as the year progresses.
4. Your Houseplant Is Experiencing Guttation
The liquid dripping from your plant may be xylem sap. Plants are living creatures that regulate the amount of water circulating in their body. If there’s too much at any time, plants can excrete excess water through spores in a process known as guttation.
Guttation is a natural part of water regulation. Still, if you notice water droplets dripping from your houseplant too often, it may indicate that you’re overwatering the plant.
How Is Guttation Different From Transpiration?
Guttation and transpiration are technically different, although they have a lot in common. Transpiration is the loss of water vapor through specialized pores in plant leaves called stomata. It occurs during the day and serves an important purpose.
When water vapor exists during transpiration, it causes the roots to draw in more water. You can think of transpiration as a plant “exhaling” water vapor.
Interestingly, the majority of water a plant gathers exits via transpiration. A significant part of the remainder is lost via guttation, and only a tiny percentage is used in metabolism.
Guttation occurs mainly at night when water can’t escape via transpiration because all the stomata have closed up. The process seeks to eliminate any excess water content in the plant body.
High humidity and soil moisture commonly cause plants to experience guttation. The water is secreted through hydathodes that line the edges of plant leaves, which also explains why there’s often a lot of dripping involved.
The release of xylem sap in guttation doesn’t harm plants, so it’s not a cause for concern.
Overwatering Can Lead to Guttation
Guttation is not a problem, at least in terms of your plant’s health. However, frequent and intense guttation may indicate overwatering since a high soil moisture level is a primary cause of this behavior.
If you give your houseplant too much water too often, you can end up overwatering it. Unfortunately, this is very common because we tend to greatly overestimate how much water plants need.
Overwatering can also be caused by the lack of drainage, which is why you should always use a container with a drainage hole.
The consequences of overwatering aren’t restricted to excessive guttation. Overwatering can have disastrous effects on the health of your houseplant because it can cause waterlogged soil, which can cut off root access to oxygen. Roots can’t hold their breath for too long and eventually begin to suffocate and eventually rot.
If the excess water isn’t drained away soon, the engulfed roots will drown and die off. Without a way to supply itself with nutrients and water from the soil, the whole plant shortly follows suit. And that’s not all—the decaying roots will then attract fungus gnats, seemingly as if to add insult to injury.
Signs of Overwatering
Other than the dripping sap caused by excess guttation, here are a few more common and easier-to-identify symptoms of overwatering:
- Stunted growth
- Foliage is losing color
- Wilted leaves that don’t perk up when watered, which means root damage has set in
- Black roots
Black, soggy roots, otherwise known as root rot, are the telltale sign of overwatering. To confirm your suspicion, it’s best to dig a few inches (about 5 cm) deep into your plant’s growing media and examine the roots themselves.
How to Fix
Saving an overwatered plant is difficult but it’s not impossible. Whether or not a plant manages to recover successfully depends largely on the severity of damage done to its roots.
If it still has a healthy root or two left, chances are it could recover, given enough time and care. However, if all the roots appear to be in equally horrible shape, chances of recovery are slim. Overwatering is a menace best prevented.
Essentially, plants with root rot must be removed from the old soil, pruned of dead or decayed roots, and repotted into fresh and sterile soil. To learn more about the process, you can read my article: How to Fix Root Rot in Houseplants.
The good news is that if all you’re seeing is noticeable guttation in the mornings and not any of the other symptoms associated with overwatering, your plant may just have absorbed more water than it can transpire.
Prevention is better than cure and it’s best to prevent overwatering or guttation through the following:
- Water your houseplant in the morning to give your plant time to release the excess moisture throughout the day.
- Maintain optimum temperature and humidity levels around your plants. Low temperatures and high humidity slow down moisture evaporation from the soil and increase the likelihood of guttation.
- Use a well-draining substrate. Always choose potting mixes suitable for your plant’s moisture needs. A potting mix that holds too much moisture can quickly lead to overwatering issues, which your plant may manifest early on through guttation.
- Check the soil moisture before watering. Each plant has a different moisture requirement. Confirm that the soil is dry enough before watering your plant again to avoid overwatering.
Summary
Your houseplant dripping substance is most likely honeydew. It looks quite similar to sap and is caused by pests. If you examine your plant’s foliage and spot pests, you should deal with them immediately to prevent spread and reproduction.
A houseplant can also leak sap for a while after an injury, which is self-resolving. However, you should check for extrafloral nectaries, which are located on the stems and leaves.
Lastly, reevaluate your current watering routine. Plants release xylem sap from their leaves when they have excess water in their body, which may be the cause of dripping sap.
