Roly polys appear in almost every garden, basement, and mulch bed, but most homeowners have no idea what keeps these armored critters coming back. Understanding what roly polys eat helps you decide whether they belong in your yard or need to be managed before they damage your plants.
This guide explains the diet of roly polys, where they find food around your property, when they become garden pests, and how to work with or control them based on what attracts them to your space.
What Do Roly Polys Eat in Your Garden and Home?
Roly polys eat decaying organic matter including dead leaves, rotting wood, decomposing plant material, fungi, and algae. They are detritivores that break down waste in soil and mulch, occasionally feeding on tender seedlings, young roots, and soft fruits when decomposing material is scarce or moisture levels are high.
Why Roly Polys Are Drawn to Your Yard
Roly polys are not insects. They are terrestrial crustaceans related to shrimp and lobsters, and they need moisture to survive because they breathe through gill-like structures.
Your garden offers the damp, dark conditions they require. Mulch beds, leaf litter, compost piles, stacked firewood, rocks, landscape timbers, and the soil under potted plants all hold moisture and provide shelter during the day.
These creatures are most active at night and hide during daylight hours. If you lift a board, pull back mulch, or move a flowerpot and find dozens of roly polys, the area is staying wet long enough to support them.
The Primary Diet: Decomposing Plant Material
Roly polys feed mainly on dead and decaying organic matter. This includes fallen leaves, rotting bark, decomposing roots, old mulch, and plant stems that have started to break down.
They scrape and chew soft, decomposing tissue with their mouthparts. As they eat, they speed up the breakdown of organic material and return nutrients to the soil, which benefits most garden plants.
What They Prefer to Eat
Roly polys prefer material that has already begun to rot. Fresh, healthy plant tissue is too tough and dry for them to consume efficiently.
They are particularly attracted to these food sources:
- Wet, decomposing leaves
- Rotting wood and bark
- Decaying mulch
- Old vegetable scraps in compost
- Fungi and mold growing on damp surfaces
- Algae on pots, stones, or soil
- Dead roots and tubers in the soil
When Roly Polys Eat Living Plants
Roly polys occasionally feed on living plant tissue when their preferred food is limited or environmental conditions favor high populations. This behavior is more common in spring when seedlings emerge and in very wet seasons.
They target soft, moisture-rich plant parts. Young seedlings, tender new roots, strawberries, tomatoes touching the ground, and the stems of seedlings are all vulnerable.
Signs of Roly Poly Damage
Damage from roly polys looks different than insect feeding. They create irregular holes in leaves and fruits, often starting at the edges or where the plant touches moist soil or mulch.
Seedlings may have stems chewed at the soil line, similar to cutworm damage. Check for roly polys at night with a flashlight, or place a damp board near affected plants and lift it the next morning to see if they are hiding underneath.
Roly Polys in the Compost Pile
A healthy compost pile often contains hundreds of roly polys. They are beneficial decomposers in this setting and help break down kitchen scraps, yard waste, and other organic material.
Their feeding accelerates decomposition and improves compost texture. If you turn your compost and see roly polys, leave them alone—they are doing valuable work.
How Roly Polys Benefit Your Garden
In most situations, roly polys are helpful members of the soil ecosystem. They consume decaying material that would otherwise sit on the surface or in the top layer of soil.
As they digest organic matter, they produce waste that enriches the soil with nutrients. Their tunneling also improves soil aeration, though the effect is modest compared to earthworms.
Roly polys are prey for birds, toads, spiders, and ground beetles. A population of roly polys supports these beneficial animals and contributes to a balanced garden ecosystem.
When to Manage Roly Poly Populations
You need to manage roly polys when they begin feeding on living plants or when their numbers grow so large that they move indoors. High populations usually indicate excess moisture and abundant decaying material.
If you are losing seedlings, finding chewed strawberries, or noticing damaged young transplants, it is time to reduce moisture and remove hiding spots near vulnerable plants.
Reduce Moisture Around Plants
Roly polys need damp conditions to survive. Cutting back on water and improving drainage makes your garden less attractive to them.
Pull mulch back a few inches from the base of seedlings and young plants. Water early in the day so the soil surface dries before evening, and avoid overwatering container plants.
Remove Hiding Spots
Eliminate places where roly polys shelter during the day. Move firewood away from garden beds, pick up fallen leaves regularly, remove old boards and landscape fabric, and elevate pots off the ground with pot feet or bricks.
Clear away decomposing mulch and replace it with fresh material if the old layer has become soggy and matted. This reduces both food and shelter.
Create Physical Barriers
Protect seedlings with cutworm collars made from cardboard tubes, plastic cups with the bottoms cut out, or strips of aluminum foil pressed into the soil around the stem. These barriers prevent roly polys from reaching tender plants at night.
Raised beds with hardware cloth at the bottom reduce populations by improving drainage and limiting access. Copper tape around the base of containers may deter them, though it is more effective against slugs.
Safe Control Methods for Roly Polys
If you need to reduce roly poly numbers, start with non-chemical methods that remove them without affecting other garden life. Most homeowners can manage populations without pesticides.
Set traps using damp rolled newspaper, cardboard, or hollowed-out potato halves placed near affected plants at dusk. Check traps in the morning, collect the roly polys, and dispose of them in a sealed bag or relocate them to a compost pile far from sensitive plants.
When to Use Pesticides
Pesticides are rarely necessary for roly polys and often harm beneficial insects, spiders, and other decomposers. If you choose to use a pesticide, select one labeled for sowbugs and pillbugs—the common names for roly polys—and apply it only to areas where damage is occurring.
Follow label instructions exactly, including rates, application methods, and re-entry intervals. Keep children and pets away from treated areas until the product has dried or as directed.
Diatomaceous earth, a non-toxic dust made from fossilized algae, can be sprinkled around the base of plants. It damages the exoskeleton of roly polys and causes them to dehydrate, but it must stay dry to work and needs reapplication after rain or irrigation.
Roly Polys Indoors: What Attracts Them
Roly polys wander indoors when outdoor conditions become too dry or when populations are very high. They enter through gaps under doors, cracks in foundations, and openings around pipes or vents.
Indoors, they search for moisture and food. Basements, laundry rooms, bathrooms, and crawl spaces with high humidity attract them, especially if there is dampness from leaks, condensation, or poor ventilation.
Preventing Indoor Invasions
Seal entry points with caulk, weatherstripping, or door sweeps. Repair leaks, improve ventilation in damp areas, and use a dehumidifier in basements if moisture levels stay high.
Remove any decaying wood, cardboard boxes stored on damp floors, or piles of old newspapers. Roly polys that make it inside usually die quickly because indoor air is too dry, but fixing moisture problems prevents future invasions.
Roly Polys and Soil Health
A modest population of roly polys signals healthy soil conditions with plenty of organic matter and adequate moisture. Gardens with diverse decomposers, including roly polys, earthworms, and beetles, tend to have better soil structure and nutrient cycling than sterile, pest-free environments.
If you are building soil health with compost, mulch, and organic amendments, expect to see more roly polys. Their presence is not a problem unless they begin feeding on living plants or their numbers grow so large that they cannot find enough decaying material.
Distinguishing Roly Polys from Sowbugs
Roly polys and sowbugs eat the same foods and live in the same habitats, but they are different species. Roly polys roll into a ball when disturbed, while sowbugs have two tail-like appendages and cannot roll up.
Both are harmless to humans and play the same role in the garden. Management strategies work equally well for both, so identification is mostly a matter of curiosity rather than control.
Feeding Roly Polys Intentionally
Some gardeners and educators keep roly polys in terrariums to observe decomposition or as low-maintenance classroom pets. In captivity, they eat sliced vegetables like carrots, potatoes, zucchini, and lettuce, along with dried leaves, rotting wood, and fish food.
Provide a damp substrate of coconut coir or soil, and mist the enclosure regularly. Add a piece of bark or cardboard for shelter, and remove uneaten food before it molds.
Managing Your Garden with Roly Polys in Mind
Understanding what roly polys eat helps you make better decisions about mulch, moisture, and plant protection. In most gardens, they are beneficial recyclers that support soil health without causing noticeable damage.
Start by improving drainage, reducing excess moisture, and keeping mulch away from tender plants. If damage occurs, use physical barriers and traps before considering pesticides, and remember that a few roly polys are a normal part of a living, functioning garden ecosystem.