Roly-Polies in Houseplant Pots: A Calm Guide to Pillbugs and Sowbugs

You lift a potted plant to water it and something small and gray rolls across the saucer.

When you touch it, it curls into a tight little ball.

A few more are hiding under the pot, close to the drainage hole.

Many people call them roly-polies.

Their proper names are pillbugs and sowbugs.

They look a little alarming in a living room, but they are rarely a real threat to a houseplant.

This guide explains what they are, why they show up in pots, and how to send them back where they belong.

It follows the University of California Statewide Integrated Pest Management Program and its page on pillbugs and sowbugs.

What Pillbugs and Sowbugs Are

Pillbugs and sowbugs are not insects at all.

The UC program explains that they are soil-dwelling crustaceans in the order Isopoda.

That makes them distant relatives of shrimp and crabs rather than beetles.

Adults have seven pairs of legs.

Insects, by comparison, have three pairs.

Their backs are covered with a series of hard, segmented plates.

Adults are about one third to three quarters of an inch long.

Their antennae are roughly a quarter of the body length.

Young ones are pale yellow to whitish and very small when they first appear.

Older ones turn brown to dark gray.

A freshly molted one can even look blue or purplish for a short time.

How to Tell Them Apart

The two look alike, but a few simple clues separate them.

  • Pillbugs curl into a ball when disturbed, which gives them their name.
  • Sowbugs cannot roll up and usually scurry away instead.
  • Sowbugs are a bit flatter on top than pillbugs.
  • Sowbugs have two small appendages sticking out at the rear end.
  • Pillbugs have a smooth, rounded rear end.

For your plants, the difference does not matter much.

Both live the same way and respond to the same calm steps.

What They Eat

According to the UC program, these animals feed mainly on decaying plant material.

Outdoors they are important decomposers that help break down fallen leaves.

They usually hide under organic litter, debris and low-growing plant parts.

They can occasionally chew seedlings, new roots and lower leaves.

They also nibble soft fruit and vegetables that touch damp soil.

In a houseplant pot, that means they are mostly eating dead leaves and old organic matter.

A large, steady group in a small pot can still nibble tender roots or a low leaf.

So it makes sense to move them out, without panic.

Why They End Up in Pots

Pillbugs and sowbugs need moisture to survive.

They gather where it stays damp and dark, with something soft to eat.

A few common situations bring them into contact with houseplants.

  • A pot spent the summer outdoors and sat directly on soil, mulch or a damp patio.
  • A saucer under the pot stays full of water for days.
  • Fallen leaves are left to rot on the soil surface.
  • Plants by an entry door are close to mulch or leaf litter outside.

The UC program notes that they sometimes come indoors on their own and become a nuisance.

They do not usually last long in a dry room.

A damp pot, however, gives them a small island where they can stay.

Step 1: Look Before You Act

Start with a quiet inspection.

  • Lift the pot and look at the bottom and around the drainage hole.
  • Check the saucer and the shelf or floor right under the pot.
  • Gently move any dead leaves lying on the soil.
  • Look at the lowest leaves for small chewed edges.

A few roly-polies under the saucer are a mild problem.

Dozens living in the soil mean the pot is staying too wet.

Step 2: Clear the Soil Surface

The UC program recommends reducing the decaying organic matter on the soil.

In a pot, that is easy to do.

  • Pick up fallen leaves and flowers from the soil.
  • Trim leaves that are yellow and resting on the soil surface.
  • Remove any thick layer of old leaves or loose bark that stays damp.
  • Wipe the saucer clean.

With less food and fewer hiding places, the pot becomes much less inviting.

Step 3: Let the Surface Dry

The UC program also recommends keeping the soil surface less wet.

It suggests watering less often, to the extent that the plant stays healthy.

That fits the advice from the University of Maryland Extension for indoor plants.

It recommends watering by need instead of by a fixed schedule.

Check the soil about two inches down before you water.

The same source warns against leaving a pot sitting in water.

Empty the saucer a short while after each watering.

The UC program also suggests watering early in the day.

That way the surface has time to dry before evening, when these animals are most active.

Our guide on how to water indoor plants walks through the full routine.

Step 4: Move the Visitors Outside

You do not need sprays for a few pillbugs or sowbugs.

The UC program focuses on moisture and debris rather than chemicals for these animals.

  • Scoop up the ones you see with a piece of paper or a small cup.
  • Release them outdoors near a compost pile or under shrubs, away from the house.
  • Sweep up any that wander across the floor.

Outside, they go back to their useful work of breaking down leaves.

If many are living deep in the soil, gently tip the plant out over newspaper.

Shake off the visitors and old debris, then return the plant to the pot.

Use fresh potting mix to fill any gaps, and keep the surface tidy afterward.

Step 5: Keep Them From Coming Back In

The UC program lists several ways to stop pillbugs and sowbugs from entering a home.

  • Install weather stripping and door sweeps.
  • Seal or screen gaps and openings in the building.
  • Keep irrigation water away from the foundation, especially near doors.
  • Keep plants, mulch and debris at least several inches from the foundation.
  • Keep that zone even wider near entrances.
  • Reduce bright outdoor lights, or try motion-activated or yellow lighting.

It also suggests keeping compost and mulch back from plants and building foundations.

For potted plants on a patio, set them on pot feet or a stand instead of directly on damp ground.

That simple gap makes the pot less appealing as a daytime shelter.

Similar Small Creatures in the Pot

Other tiny visitors can show up in damp potting soil too.

  • Tiny pale specks that jump are likely springtails.
  • Small dark flies near the soil are often fungus gnats.
  • Lines of small insects walking up and down the pot are probably ants.

Read our guides to springtails, fungus gnats and ants in houseplants if they sound more familiar.

Many of these share one cause: soil that stays wet for too long.

Fixing the watering often solves more than one problem at once.

If Pets Live With You

Pillbugs and sowbugs are not a reason to reach for strong products indoors.

If you ever use any product near your plants, read the label carefully and follow it exactly.

Also check that your houseplants themselves are safe for pets.

The ASPCA list of toxic and non-toxic plants is a helpful place to look.

A Calm Checklist

  • Seven pairs of legs and a shell of plates means pillbugs or sowbugs, not insects.
  • They mostly eat decaying leaves and only rarely chew roots or seedlings.
  • Clear dead leaves and old debris from the soil surface.
  • Water by need, early in the day, and empty the saucer.
  • Move the visitors outside by hand instead of spraying.
  • Seal gaps and keep mulch back from doors and foundations.
  • Raise outdoor pots off damp ground.

A few roly-polies in a pot are simply a sign that it stays a little too damp.

Dry it out, tidy the surface and give them a ride back outside.

Your plant will be fine, and the garden gets its helpers back.

Sources and Further Reading