Can Pill Bugs Damage Plants? 11 Things to Know

Pill Bug Armadillidiidae on rotting leaf

Pill bugs, Roly polies, potato bugs, and doodle bugs are all common names for this critter. You will find them living on the forest floor, in our gardens, under logs, in aged firewood, and in other moist places.

Pill bugs break down decaying matter and turn it into soil. However, when their favorite food source has been consumed or removed, they turn to fresh leaves and fruit for nourishment. They can cause significant damage to seedlings by feeding on the fresh stem tissue.

The common pill bug is native to Europe but has become well-established in many parts of the world, including the United States. Read on to learn 11 important things to know about how to live with this interesting arthropod and still grow healthy, happy plants in an organic garden!

Key Takeaways:

  • Pill bugs usually consume decaying leaves and plant matter, but when their food sources are scarce, they will turn to living plants.
  • Pill bugs are usually beneficial to have in the soil because they help break down organic matter, increasing the soil nutrients.
  • Providing pill bugs with decaying plant matter will help deter them from your living plants.

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1. Pill Bugs Live In Dark, moist Places

Pill bugs prefer dark, shadowy, and moist places where decomposing plant material decays the fastest. Their small flattened bodies with curved, jointed antennae make them very well adapted to move around in the dark while they are searching for food. 

You will often find them living in leaf litter, wood mulch, under the bark of dead trees, and many other places with rotting wood. Have you ever experienced inhaling that smell of the earthy richness of the forest? Ah yes, this is where you will find pill bugs!

They can even make their way into your potted plants! To learn more about removing them, check out Tips For Removing Pill Bugs In Potted Plants.

2. Pill bugs are Sensitive to Moisture

Pill bug rolled up on green grass

Pill bugs are very sensitive to the right moisture conditions, which is why they usually feed at night while there is high relative humidity. During dry times or when threatened, pill bugs roll up into a ball. They do so to conserve water and protect them from an attack. 

While they do like moisture, they do NOT like it too wet! Flooded soils are not the preferred habitat for pill bugs.

Temperature is an important factor to pill bugs as well. An article from the Sultan Qaboos University Journal of Science compared different characteristics at 57F and 70F. They found that at 70F, pill bugs ate more and used the food to convert to nutrients and body mass more.

3. Pill bugs hate acidic things, including acidic soils

You are less likely to find pill bugs in soil that has been tilled recently, is too wet, or has a very low acidic pH. Their preferred habitat has a neutral to alkaline pH. By tilling soil, you will disturb pill bugs’ feeding habitat and where they seek shelter.  

If your garden naturally has acidic soil, you probably add lime to your soil each year. This will raise the pH and make a more suitable pill bug habitat. Most garden vegetables prefer more neutral or alkaline soil with a pH of 6.5-7.5.

Consider growing plants that like acid soils, like hydrangeas, azaleas, rhododendrons, and camellia bushes! This will save you from needing to add lime and will naturally repel pill bugs!

4. Pill bugs love organic matter in the Garden

You have probably found pill bugs in your garden. Especially if you are diligent about adding organic matter each year to improve soil health.

Many gardeners add organic matter like straw, manure, compost, wood mulch, leaves, and other local products available to them. This organic matter will help improve soil texture, fertility, and water retention. It will also provide a great habitat for our little roly-poly friends.

Pill Bugs Are Beneficial To Have Around

Remember, these creatures shred up organic matter to turn it into rich soil. They can be incredibly beneficial to have on your side while building soil in the garden. Take mental notes about where you see them living in the garden. Do they have plenty of organic matter to keep them moist, fed, and under cover from predators? 

If they do not have the habitat they need to support their population, pill bugs target the tender stems of sprouting seedlings. Unfortunately, this will often cause plant death.

5. A Healthy Habitat For Pill Bugs Means No Feeding On Your Plants!

Like any other pest, if pill bugs can find food in their natural environment, they’re likely to leave your living plants alone. You want them to continue to help you have healthy soil while keeping them under control so they do not turn to tender seedlings for food.

A primary benefit of growing plants organically is working in tandem with nature’s processes. Instead of adding harsh chemicals to the environment to get rid of populations, we understand there is a natural balance of beneficial insects, predatory species, and yes, pests!

Here are some common places where pill bugs like to hide:

LocationReason for Pill Bug Presence
Under rocksProvides shelter and protection from predators
Moist soilHelps prevent desiccation and provides food
MulchOffers a damp and dark environment
Rotting woodProvides food and shelter
Garden debrisOffers hiding spots and food sources

Allowing these places to exist in your yard will help keep pill bugs fed on things that aren’t your garden vegetables or flowers!

6. The Other Side of The Coin: Keeping Pill Bugs Away

The first five items on our list have all been about providing pill bugs with a nice, comfortable environment with plenty of food. This way, they feed on decaying organic matter and leave your living plants alone.

Now we’re going to discuss some ways to keep these arthropods away. We always believe that letting nature do its thing is the best option, but sometimes, these creatures can really take over your garden and you need to repel them or work to keep them away.

Here are our suggestions:

Avoid Giving Pill Bugs Food

When adding organic matter, use well-rotted organic matter in your gardens to combat pill bugs. This will solve a few potential other problems as well, such as dampening, molds, fungi, and other decomposing pests that thrive in a high organic matter content.

If you are making your own compost to add to garden soil, it is a worthwhile measure to screen out the larger items before adding them as an amendment. Next, be sure to mix it well with the existing soil.

To sift your soil, push it through a screen frame, like this one from KS Kabells Sifter for Garden. It is a clever design meant for use with a wheelbarrow. Anyone who has sifted soil will appreciate the thoughtfulness since moving compost around is heavy work!

But Be Careful…

By creating an environment where there is no natural food for pill bugs, this could create a whole new problem – pill bugs targeting your plants.

If you decide to remove pill bug food sources, it will be crucial to also treat your plants to keep pill bugs off of them. You can read about the best pill bug sprays and powders here.

In some ways, this option may create more problems than solve. That said, there is the chance that pill bugs will move away from this area to another area of the yard with a food source available, helping to solve your problems!

7. Add Leaves or Straw In The Fall

Covering young capsicum plants with straw mulch to protect from drying out too quickly.

Usually in the fall, many gardeners will add a cover crop along with leaves or straw to their garden beds. Thanks to the mighty decomposers who call our gardens home, by springtime these mulches are already rotting away, but not always.

Rototiller Leftover Organic Materials…or not

In the spring, we face the decision to mix the remaining organic matter into the soil or to rake out the larger chunks from the surface and compost them. If you have access to a rototiller, this is a good option since there are some benefits to just chopping it up in the soil at this point.

By removing the excess plant material from the surface of the garden soil, you are also removing the habitat (and food!) for pill bugs. LIke our option above, this could create the problem of making pill bugs target your living plants since there is no decaying material for them to eat.

Instead of tilling the garden, you could take the leftover organic material and place it in a compost. This could be the best of both worlds, leaving some decaying materials for pill bugs to feed while removing the larger chunks so that populations don’t explode.

8. Use barriers to protect your seedlings From Pill Bugs

If you are anything like me, whenever there are young seedlings in the garden, I will protect them as best as I can! Once garden plants are bigger and sturdier, pill bugs shouldn’t bother those tender stems anymore. Keep this in mind when planning this phase of protection—it is only for a short time!

Diatomaceous Earth

For the small home garden, an effective control is diatomaceous earth. This natural material is abrasive to crawling insects and you can use it as a barrier to protect plants when dry. Simply pour the powder around (or sprinkle lightly on top of) the young seedlings.

Diatomaceous Earth by Earthborn Elements comes in a resealable bucket. The abrasive material in diatomaceous earth makes it nearly impossible for pill bugs to crawl over.

The major downside of using diatomaceous earth is that when it gets wet, it is not very effective. Also, it is non-selective in what insects it could harm so may eliminate ‘good bugs.’

Canning Jars

I’ll admit to also using wide-mouth canning jars atop my young seedlings as they are first emerging from the soil. The jars are heavy enough to withstand winds and weather and will also keep unwanted pests from eating the young sprouts.

The biggest concern here is when the heat of the day arrives, the jar becomes a solar oven and can quickly bake the seedlings!

Only use this method if you can monitor your plants throughout the day or at least take off in the morning after the slugs, snails, and pill bugs have gone into hiding.

Scent Barriers

Using scents and smells that repel pillbugs is another option to keep them away. It’s a relatively cheap and natural alternative to using harsh chemicals and commercial sprays.

Some of the scents that can deter pill bugs include:

  • Dried coffee grounds
  • Cayenne pepper
  • Garlic
  • Cinnamon
  • Peppermint

For a complete list of scents, head over to our article on scents that pill bugs hate for nine smells that ward off these roly-poly creatures.

9. Protecting Your Fruits From Pill Bugs

We have learned pill bugs prefer a diet full of decomposing matter. In the instance of growing a garden with little to no fresh organic matter, they may eat sprouting seeds and young seedlings such as melon, Swiss chard, potato, cucumber, lettuce, spinach, cucumber, beets, peas, corn, and soybeans.

Use A Trellis To Keep Pill Bugs Away

Pill bugs can cause significant damage to fresh strawberries and melons growing on the ground. However, you can grow melons vertically on a trellis. The American Garden Works Narrow Screen Trellis is made of steel and is plenty sturdy to grow heavy fruit like melons!

Landscape Fabric Can Protect Fruits

When growing a strawberry patch, many farmers use landscape fabric as a semi-permeable moisture barrier to keep weeds down, hold moisture in, and provide a physical barrier between the berries and the bare ground.

This would also create a barrier between fruit and pill bugs. Simply lay the cloth out across the garden soil, cut X’s every 12 inches apart, and plant the strawberry plants. Be sure to secure the cloth to the ground so it does not blow away!

Use Specialized Containers

There are also many other clever ways to make a strawberry tower, and there are specially designed pots and containers for growing strawberries off of the ground, like the Reeyox Strawberry Grow Bag.

Since pill bugs are usually found feeding on the ground, your fruit will be much more protected if they are raised! By doing this, you are also improving air circulation and using garden space wisely!

10. Improve Air Circulation to keep Pill Bugs away

To reduce habitat in a garden, we need to reduce shady, moist places. Use vertical gardening strategies, such as trellis’ to get plants off of the ground. This will improve air circulation and reduce the type of microhabitats pill bugs prefer the most.  

Vertical Gardening

Vertical gardening is a form of gardening worth learning more about, especially if you are gardening in a small space. There are so many other great gardening strategies employed with this method.

If you are open to learning more, check out this book by Mel Bartholomew called All New Square Foot Gardening, 3rd Edition. They claim the form of gardening they teach has helped millions of home gardeners enjoy their garden with less work and space.

From my experience, I would agree! Cucumbers to melons, squash, and all of those vining crops pill bugs also love now grow up a trellis, with a bit of training.

11. Hot Soil will Repel Pill Bugs

Adult Pill Bug Armadillidium vulgare crawling on twig.

How To Heat The Soil

Add black plastic or tarps to garden soil and let bake in the sun for a week. This is an effective method to kill off cover crops without tilling while getting some side benefits. Cover and heat the soil each early spring, providing benefits such as seed germination, pest control, and weed management.

Most seeds will germinate faster in warm soil, rather than cool soils. But before you get too ambitious with planting your garden, read on to learn how this method will repel pill bugs. 

How Warm Soil Repels Pill Bugs

Since pill bugs are sensitive to moisture and heat, they will leave an area no longer suitable for their survival. In this case, they would get cooked by the heat and humidity! This will also be true for other garden pests lying beneath the soil surface as well.

The Benefits Of Warm Soil

Other benefits of heating the soil include germinating unwanted weed seeds before planting the seeds you want to grow. Be sure to turn the soil over or till it after they have sprouted. Sprouting weeds on purpose a few times before planting can save a lot of time and energy throughout the growing season. 

Use a black vapor barrier plastic such as the Farm Plastic Supply- Black Plastic Sheeting. It comes in 3-foot by 100-foot rolls you can simply roll out on top of garden soil. Use loose soil, rocks, or staples to pin the edges down.

It can also be doubled and used as mulch to reduce weeds or pathways between garden beds! As with any plastic product, check your local recycling programs to dispose of it responsibly.

That’s a wrap!

Plants can bring us so much joy, but it can also be so defeating when our hard work (and money!) does not turn out how we envisioned. It can be easy to overreact and declare war on whatever pest is causing damage.

I urge you not to wage war on the pill bug. Their ecosystem services far outweigh the damage they are likely to cause in a home garden, especially if you adopt some of the tips in this article and put them into practice. 

However, if you really want to get rid of these pests, we’ve provided ways for that too! You can also use our nationwide pest control finder to connect with a local professional in your area to help out with any pill bug problems and to get guidance on how to control them.

References

W. A. Johnson, S. Alfaress, R. J. Whitworth, B. P. McCornack, Crop Residue and Residue Management Effects on Armadillidium vulgare (Isopoda: Armadillidiidae) Populations and Soybean Stand Densities, Journal of Economic Entomology, Volume 105, Issue 5, 1 October 2012, Pages 1629–1639

Smigel, J. T., & Gibbs, A. G. (2008). Conglobation in the Pill Bug,Armadillidium vulgare, as a Water Conservation Mechanism. Journal of Insect Science8(44), 1–9

Gillman, Jeff. The truth about organic gardening: benefits, drawbacks, and the bottom line. Timber press, 2008.

Youssef, A. K., & Nair, A. (2004). Thermal Effects on the Body mass, Transpiration rate, Feeding and Food Conversion of the Pillbug Armadillo officinalis (Isopoda, Oniscidea) Fed on the Dry Leaf of Punica Granatum. Sultan Qaboos University Journal for Science [SQUJS]9, 1-5.

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