You pick up a potted plant to water it, and a line of small ants hurries across the saucer.
A few more come out from the drainage hole.
Others are walking up the stems, busy and purposeful.
Ants on a houseplant can feel unsettling, but the cause is usually simple.
They are either collecting food from the plant or using the pot as a home.
Sometimes it is both.
This guide follows the University of California Statewide Integrated Pest Management Program and its Pest Notes on ants.
We adapt that research for plants that live inside a home.
Why Ants Visit Houseplants
Ants usually come indoors looking for food, water, warmth, or shelter.
A houseplant can offer all four.
The most common draw is honeydew, a sweet, sticky liquid.
Aphids, soft scales, mealybugs, and whiteflies excrete it while they feed on plant sap.
The UC program explains that ants tend these insects to collect their honeydew.
In return, the ants protect them from their natural enemies.
That protection can increase the damage these sap feeders cause.
So ants climbing a plant are often a sign of another pest hiding there.
A pot can also become a nest.
The UC program lists potted plants among the indoor nesting sites worth checking.
Some species prefer warm, moist places, and a watered pot in a heated room fits that description.
First, Look Closely
Spend a few minutes watching before you do anything.
Where the ants go tells you what they want.
- Ants walking up and down the stems are probably visiting honeydew.
- Sticky, shiny leaves or a black sooty film confirm that honeydew is present.
- Ants carrying small white eggs or larvae point to a nest in the pot.
- Ants streaming in and out of the drainage hole suggest the same.
- A line of ants crossing the floor shows where they enter the room.
Turn several leaves over and check the leaf joints and new shoots.
A magnifying glass helps you spot aphids, scales, or mealybugs.
If the Ants Are After Honeydew
In this case, the ants are only half of the problem.
Manage the sap-feeding insects, and the ants lose their reason to visit.
- Rinse sturdy plants in the sink or shower with lukewarm water.
- Prune heavily infested shoots and bag them for the trash.
- Wipe honeydew from leaves, pots, and the surface below.
- Use insecticidal soap or oil only if gentler steps are not enough.
Our guides explain each insect in more detail.
See aphids, mealybugs, scale insects and whiteflies.
If you also see a black film on the leaves, our guide to sticky leaves and sooty mold explains how to wash it off.
If Ants Are Nesting in the Pot
The UC program describes a simple way to clear a nest from a potted plant.
- Take the pot outdoors, away from the house.
- In a bucket or tub, mix 1 to 2 tablespoons of insecticidal soap per quart of water.
- Set the pot in the solution so the surface of the soil is just covered.
- Leave it there for 20 minutes or more.
- Lift the pot out and let it drain completely before bringing it back inside.
Read the insecticidal soap label before you start and follow it.
Use a soap product sold for use on plants, not a household cleaner.
Choose a bucket or tub wide enough for the pot to sit flat on the bottom.
A large pot full of wet soil is heavy, so ask for help if you need it.
After the soak, let the soil dry to its normal watering point before you water again.
The University of Maryland Extension recommends watering most houseplants when the soil is dry about two inches down.
It also warns never to let a houseplant sit in water.
Clean Up the Ant Trails
Ants leave a scent trail that guides other ants to food.
The UC program recommends cleaning up invading ants with a sponge and soapy water as soon as they appear.
Soapy water removes the scent trail, especially when you clean the spots where ants enter.
Vacuuming a trail works too.
The UC program notes that indoor insecticide sprays usually are not necessary.
Spraying ants indoors will not stop more ants from coming in.
Find Where They Come In
Most ants live outdoors and enter in search of food and water.
Follow a trail back to where it starts, if you can.
Ants like to travel along pipes and wires, which often lead them inside.
The UC program recommends sealing cracks and entry points with caulk.
For a quick fix, it mentions plugging an opening with petroleum jelly until you can caulk.
Look also at plants growing right outside the window or door.
The UC program suggests managing sweet food sources next to the house, such as shrubs full of aphids.
Make the Room Less Inviting
- Store sugar, honey, syrup, and pet food in clean, sealed containers.
- Wipe up crumbs, grease, and spills promptly.
- Rinse out empty drink containers before they go in the recycling.
- Take out the trash and food waste often.
- Fix leaky faucets, since water attracts ants too.
- Empty water from plant saucers after watering.
The UC program lists most of these steps as ways to make a home less attractive to ants.
The last one helps your plants as well.
A Note on Baits
If ants keep returning, the UC program names baits as the key tool for most situations.
Worker ants carry bait back to the nest and share it, which can affect the whole colony.
The UC program recommends using baits mainly outdoors, near trails and nest openings.
Baits placed indoors can draw ants inside, so it suggests that only for serious cases with no clear entry point.
Prepackaged bait stations are the simplest and easiest to use.
Keep them out of reach of children and pets, and follow the label exactly.
Baits take time, and the UC program notes it can take 5 to 10 days to see fewer ants.
It also advises against using insecticide sprays while you use baits.
If you share your home with pets, check every plant in the ASPCA list of toxic and non-toxic plants.
How to Keep Ants Away From Your Plants
- Check new shoots and leaf undersides each time you water.
- Deal with aphids, scales, mealybugs, and whiteflies early.
- Wipe honeydew as soon as you notice it.
- Keep the area around your plants free of food.
- Inspect new plants before they join your collection.
Our checklist for bringing home a new houseplant walks through that inspection.
Good watering habits help too, and our guide on how to water indoor plants explains them.
Keeping Perspective
The UC program reminds us that ants also do useful work outdoors.
They feed on other pests, such as fleas and termites, and on dead insects.
The goal is not to remove every ant, only to keep them off your plants and out of your home.
Find what they want, take it away, and close the door they use.
With that calm approach, most ant visits to houseplants end quickly.
Sources and Further Reading
- UC Statewide Integrated Pest Management Program — Pest Notes: Ants: supports why ants enter homes, ants tending honeydew producers, potted plants as nest sites, the insecticidal soap soak, cleaning trails, caulking, sanitation, baits, and the useful role of ants outdoors.
- UC Statewide Integrated Pest Management Program — Pest Notes: Sooty Mold: supports the link between honeydew, sooty mold, and ant management.
- University of Maryland Extension — Watering Indoor Plants: supports the two-inch finger test and never letting plants sit in water.
- ASPCA Animal Poison Control — Toxic and Non-Toxic Plants: the reference for checking whether a plant is safe around cats and dogs.