If you’ve ever overturned a rock or log in your garden, you’ve likely seen rolly pollies scatter. These small, armored critters are common, but their role in the garden is often misunderstood, as their diet includes both decaying matter and tender plants. So, do rolly pollies eat plants? The answer is yes, but their impact is more nuanced than you might think.
This article will explain exactly what rolly pollies eat, when they become a problem, and how to manage them in your garden effectively. You’ll learn to see them not just as pests, but as part of your garden’s ecosystem.
Do Rolly Pollies Eat Plants
Rolly pollies, also known as pill bugs, woodlice, or by their scientific name Armadillidium vulgare, are terrestrial crustaceans, not insects. This means they’re more closely related to shrimp and crabs than to beetles or ants. Their primary ecological function is that of a decomposer. They consume decaying organic material, which is vital for nutrient cycling in soil.
However, under certain conditions, their feeding habits can shift. While they prefer decaying plant matter, they will readily eat living plants if their preferred food is scarce or if the plant tissue is young, tender, and easily accessible. This typically happens in damp, mulched gardens with abundant hiding places.
Primary Diet: The Decomposer Role
In a balanced garden, rolly pollies are beneficial. They are part of nature’s cleanup crew, breaking down dead leaves, rotting wood, and other decaying vegetation. This process helps create humus and returns essential nutrients to the soil for your plants to use.
Their digestive activity also aids in soil aeration. As they move through the upper soil layers, they help create tiny channels that improve water infiltration and root growth. In this role, they are a gardener’s ally.
Secondary Diet: When They Turn To Live Plants
The shift from decomposer to plant-eater usually occurs due to environmental factors. Rolly pollies need constant moisture to breathe through their gills. During very wet periods or in overly watered gardens, their populations can boom.
At the same time, a lack of their preferred decaying food can push them to seek other sources. They are especially attracted to:
- Seedlings and young sprouts with soft stems.
- Fruits and vegetables lying directly on damp soil, like strawberries or zucchini.
- The tender leaves of low-growing plants like lettuce and basil.
- New roots on cuttings or recently transplanted starts.
They often begin feeding on decaying portions of a plant, like a ripe tomato with a small crack, and then continue eating into the healthy tissue. This makes them seem like the primary culprit, when they may have been secondary invaders.
Identifying Rolly Pollie Damage
It’s important to correctly identify the damage, as many garden pests can chew on plants. Rolly pollie damage has distinct characteristics.
They create irregular, ragged holes on leaves, stems, and fruits. Unlike slugs and snails, they do not leave a slime trail. The damage is often worst on plants touching the ground or in very damp, shaded areas of the garden. You’ll usually find them hiding under the damaged plant during the day.
Damage on Seedlings
Seedlings are most at risk. Rolly pollies can completely sever tender stems at soil level or consume the first set of true leaves, killing the plant. This is often the most frustrating damage for gardeners.
Damage on Mature Plants
On established plants, damage is usually less severe but can affect yield. They may chew on the skins of fruits like melons or tomatoes, especially where the fruit contacts wet soil or mulch. They can also damage the lower leaves of many vegetable plants.
Managing Rolly Pollies in Your Garden
Complete eradication of rolly pollies is neither practical nor desirable, given their beneficial role. The goal is management—reducing their numbers and creating an environment where they are less likely to feed on your plants.
Cultural Control Methods
These methods involve changing your gardening practices to make the area less inviting to rolly pollies seeking live plants.
- Reduce Moisture: Water plants in the morning so the soil surface dries by evening. Use drip irrigation or soaker hoses instead of overhead sprinklers to keep mulch and soil surface drier. Fix leaky faucets and ensure good drainage.
- Modify Mulching: Pull mulch back 2-3 inches from plant stems. This creates a dry barrier they are reluctant to cross. Consider using a drier mulch like straw instead of moisture-retaining wood chips in problem areas.
- Clean Up Debris: Remove decaying plant matter, fallen fruit, and old boards promptly. This eliminates their preferred food and hiding spots, encouraging them to stay in their decomposer role.
- Elevate Plants: Use stakes, cages, or trellises to keep fruits and foliage off the ground. This simple step can dramatically reduce damage to crops like tomatoes, cucumbers, and squash.
Physical And Barrier Methods
Creating physical obstructions can protect vulnerable plants effectively.
- Diatomaceous Earth (DE): Sprinkle a ring of food-grade DE around plant stems or garden beds. The sharp microscopic particles damage their exoskeletons, causing them to dehydrate. Reapply after rain or watering.
- Copper Tape: Adhesive copper tape around container rims or plant stakes can deter them. A mild electrical charge is created when their mucus contacts the copper, which they find unpleasant.
- Trapping: Place damp, rolled-up newspaper, cardboard, or half-cut grapefruit skins in the garden overnight. In the morning, gather these traps and dispose of the rolly pollies hiding inside far from your garden.
Organic And Chemical Controls
Use these methods as a last resort if cultural and physical controls are insufficient.
Iron Phosphate Baits: These are considered organic and safe for pets and wildlife. Scatter bait granules in problem areas. Rolly pollies consume the bait and stop feeding, eventually dying. This is one of the most targetted solutions available.
Insecticidal Soap: A direct spray can help reduce numbers on contact, but it offers no residual control and must be reapplied. It’s most useful for spot-treating heavy infestations on non-edible plants.
Avoid broad-spectrum pesticides. They will kill beneficial insects and soil organisms, disrupting the garden’s natural balance and potentially causing other pest problems.
Creating a Balanced Garden Ecosystem
The healthiest gardens work with nature, not against it. Instead of viewing rolly pollies as enemies, aim for a balance where their decomposing work is valued and their plant-eating is minimized.
Encourage Natural Predators
Many common garden animals eat rolly pollies, helping to keep their population in check. You can attract these predators by providing habitat.
- Birds: Install bird feeders or a birdbath. Birds, especially ground-foragers like robins and towhees, will eat large quantities of rolly pollies.
- Frogs and Toads: A small, shallow water source can attract these amphibians, which are excellent pest controllers.
- Ground Beetles: These nocturnal predators consume many soil pests. Provide permanent plantings or stone piles where they can hide during the day.
Practice Smart Planting
Adjust your planting strategy to protect vulnerable plants. Start seeds indoors or in a protected cold frame until they develop tougher stems. You can also create “sacrificial” plantings. Place a piece of raw potato or a leaf of lettuce under a board to attract rolly pollies away from your prized seedlings.
Crop rotation and diversifying your garden also helps prevent any one pest, including rolly pollies, from becoming a widespread issue.
Frequently Asked Questions
Are Rolly Pollies Bad For The Garden?
Not inherently. They are primarily beneficial decomposers. They only become a problem when their population is very high and they begin feeding on young plants or fruits. In most cases, they cause little to no significant damage.
What Plants Do Rolly Pollies Eat Most Often?
They prefer tender, succulent plants. Common targets include bean and pea seedlings, lettuce, spinach, basil, strawberries, melons, and squash fruits lying on the ground. They rarely bother plants with tough, woody stems or hairy leaves.
How Can I Tell If Slugs Or Rolly Pollies Are Eating My Plants?
The key difference is the slime trail. Slugs and snails leave a shiny, silvery mucus trail on leaves and soil. Rolly pollies do not leave this trail. Also, rolly pollies tend to create more ragged, scooped-out damage, while slug damage often has smoother edges.
Do Rolly Pollies Eat Each Other?
Yes, they can exhibit cannibalistic behavior, especially in overcrowded conditions or when other food sources are extremely scarce. This is a natural population control mechanism.
What Is The Lifespan Of A Rolly Polly?
Rolly pollies can live for 2 to 5 years, which is surprisingly long for a small garden creature. They go through a series of molts as they grow and the females carry their eggs in a special pouch, similar to their marine crustacean relatives.
Understanding the dual nature of the rolly polly diet is key to harmonious garden management. By providing ample decaying material, managing moisture, and protecting vulnerable plants, you can enjoy the benefits of these unique decomposers without sacrificing your harvest. Remember, a few holes in a lower leaf is a small price to pay for the free soil aeration and composting they provide. With the strategies outlined here, you can ensure your garden remains productive and balanced.