Q&A: How do I keep pillbugs out of my garden? Or earwigs? Or slugs?
The are dozens and dozens of insects that bother gardeners, but here we’re addressing the creepy crawly ones that live in dark, damp corners of your garden. Pillbugs (doodlebugs or roly-polys to some people), grubs, slugs and snails (actually mollusks, not insects), earwigs, and (shiver) millipedes.
First, a question for you: WHY do you want to get rid of them? And if the answer is because they’re creepy and gross, sorry, but that’s not a good enough reason.
Fact is, these bugs do serve an important purpose in the garden, and there is usually nothing to worry about if you see them in your soil. All of these insects are excellent at eating and digesting dead organic material in the soil. By eating, it, they break it down quickly and turn it into nutrients that the living plants can use to stay healthy. They also help aerate the soil and improve its structure by crawling through it and moving things around. And if you see any of these in your compost heap, celebrate! They are helping you make compost much faster than you could without them.
The problem comes when you get a population that grows too big and runs out of dead plant material to eat. Then they can start eating live plants and we don’t want that. So if you want to get rid of roly-polys because they are eating your strawberries, or slugs because your lettuce is full of holes, let’s talk.
Be Inhospitable
First, take a look at your garden environment and try to figure out why there are so many of these bugs around.
Moisture: They need to be in a moist place, so consider if you are letting the top inch of your soil dry out before watering (you should).
Wood: They also love rotting wood. If you used pine to build your raised beds, they could be happily living in those boards and eating them from the inside out. Even cedar after 10 years or so can start to succumb to this fate.
Plant debris: Do you tend to drop leaves, stems, and other bits you prune off your plants onto the soil? That’s another place these creepers love to hide. Or those yellow lower leaves of your plant that are droopy and touching the ground? Tasty treats and cozy hiding places for decomposers. Clean up the dead and dying plant material.
Take steps to make your garden less enticing for these pests and they will find another damp, dark place to live.
Play Keep Away
If you ever see one of these bugs eating your plants, get them off right away. Pick or shake them off and drown them in soapy water. If you are extra kind-hearted, move them to your compost pile. If you want to catch a lot, strap on a headlamp and look for them at night or as soon as the sun comes up when plants are still damp from dew.
Unfortunately, a slug can eat a seedling in a matter of minutes, and you can’t guard your plants 24/7, so here are some other protection methods to try:
Rough Barriers: Diatomaceous earth sprinkled around plants can create a rough barrier that many pests won’t cross, but has to be re-applied after every rain. You might also try placing window screen on the soil at the base of plants.
Cardboard or Fabric Collars: Placing collars around the base of your plants can prevent pests from crawling up the stems. These can be made from cardboard, fabric, or even aluminum foil. The goal is rough and dry material. Piece of an old wool sweater?
Copper Tape: Slugs and snails are deterred by copper. You can place copper tape around the edges of raised beds, pots, or even individual plants. When these pests try to cross the tape, they receive a small electric shock that deters them. Or wrap the stem with copper mesh.
Pedestals: A clever TKG client in Franklin lifts her strawberries off the ground and props them up on an improvised plastic fork pedestal. The berries hang suspended in the air where pillbugs can’t reach them. You can also lift squash and melons up off the soil and place them on an upside-down terra cotta saucer or a melon cradle to make it harder for soil bugs to get to the fruit.
Dead and/or Gone: Trapping and Killing Soil-Dwelling Pests
If you need to majorly reduce the population of these pests and the first two tactics haven’t helped, there are several methods for trapping and killing them. Note that some of these might also trap or kill beneficial insects, so adjust your approach if you see that happening.
Beer Traps for Slugs and Snails: Bury a shallow dish or cup so that the rim is level with the soil and fill it with beer. Slugs and snails are attracted to the beer, fall in, and drown. Make sure to check and empty the traps regularly.
Potato or Citrus Traps: Cut a potato in half or use a hollowed-out citrus fruit, and place it cut-side down in the soil. Overnight, pillbugs pests will congregate under the potato or citrus for shelter. In the morning, you can move them to the compost pile or drown them.
Cardboard, Bamboo, and Rolled up Newspaper: Can all be used as traps for earwigs. Lay them on the garden soil overnight, then dump out the bugs into a jar of soapy water in the morning.
Bait and Poison: There are organic and chemical baits available that can attract and kill these pests. Products containing iron phosphate are effective against slugs and snails and are safe for pets and wildlife. Always follow the instructions carefully to ensure safety.
Enlist help: Pay a kid a penny for every roly poly they can find and move to a better location. The bugs don’t bite or carry any diseases.
By combining a “clean” garden environment, physical barriers, and trapping methods, you can effectively manage the population of soil-dwelling pests in your garden without using chemicals. Remember, the goal is to maintain a balance where these creatures can still perform their beneficial roles without damaging your plants. Do you still want to get rid of the roly polys?
