There is nothing quite like the satisfaction and pleasure of looking out over a newly planted vegetable bed, and nothing quite as horrifying as coming back in the morning and seeing that all your efforts have been destroyed by hungry slugs and snails. Would it have been better to plant your seedlings into raised beds?
Raised beds themselves do not protect plants from slugs and snails, but raised beds make it much easier to protect plants from these pests, without having to use toxic chemical pesticides. Slug-proof raised beds with a slug fence, or by painting them with a slug-repellant coating.
Some slug fences work due to the shape of the edge, while others cause a reaction between the metal and slugs’ slime, thereby repelling them. One can even engineer a DIY electric fence to guard against slugs. Keep reading to learn of the many ways that you can use raised beds to your advantage in the battle against slugs and snails.
What Attracts Slugs and Snails to the Garden
Understanding what attracts these pests into your garden helps for long-term slug management. You can remove their hiding places or catch them and release them far away.
Snails and slugs love moist environments. Wet mulch or plant debris, ground creeping weeds, fallen logs and rocks are attractive to them.
They eat mainly leaves but can devour whole seedlings. Their favorite plants are lettuce, spinach, cabbage, zucchini, cucumbers, beans, strawberries, mustard, and cress.
Slug and snail infestations occur when they do not just visit your garden for a meal but settle down and reproduce. They lay their eggs in moist soil or under mulch, rocks, or leaves.
Slug and Snail Prevention Techniques
Prevent infestations by removing wood or stones that create moist hiding spots. Stack firewood off of the ground and check around and underneath pots regularly to catch them.
Use compost or leaf mold instead of loose mulches, like hay, straw, or wood chips, as these attract snails and slugs.
Water in the morning, rather than the evening, to avoid leaving plants foliage wet overnight. Consider drip irrigation rather than spray or overhead irrigation, to prevent wet plant foliage.
Invite more wildlife, like birds, lizards, snakes, and ground beetles into your garden, as these are slugs and snails’ natural predators. Make your garden more attractive to wildlife by planting many indigenous species and build a small pond.
Dangers of Slug Pellets and Other Pesticides
It may be tempting to simply put out some slug and snail pellets to resolve the issue, but this is a bad idea for many reasons.
Slug pellets and slug baits contain poisons that kill all mollusks, including snails, but they also contain chemicals that attract the slugs and snails to the pellets rather than your plants. These attractant chemicals are very strong and invite more snails from the surrounding area (up to 200m away) into your garden, forcing you to use more of the product.
These pesticides also contain toxins that are dangerous to pets, children, and wildlife if the pellets are ingested. The chemicals can leach from out of soils into the groundwater, polluting it. If you are growing your own fruits and vegetables, these toxic chemicals will make their way into your food.
Natural and Organic Ways to Repel Slugs and Snails
A much safer way to protect your garden from the wrath of slugs and snails is by using natural, organic strategies. Many of these methods only repel snails, without killing them and are not 100% effective. Use a combination of these methods for the best results:
- Sprinkle a 2-inch-wide barrier of crushed eggshells, coffee grounds, horticultural grit, or wool pellets around the perimeter of your garden beds, or around plants that are particularly attractive to slugs and snails. They do not like to move over these rough surfaces.
- Trap snails using live traps, which do not allow them to exit after they enter. You can then dispose of them as you wish or relocate them far away from your garden. Many snail traps, like the types that use beer or yeast, kill slugs when they enter, but many people consider these inhumane.
- A popular method for more committed gardeners is going out at night with a torch and catching all the slugs and snails by hand.
Using Raised Beds to Keep Slugs Out
While raised beds on their own do not keep slugs and snails out, they do make it easier to set up defenses against these pests. Because raised beds have a defined perimeter, it is simpler and more aesthetically pleasing to fence off your plants from slugs and snails.
Slug fences are barriers that are specifically designed to permanently keep slugs and snails out of raised beds. The angle of the curved edge prevents mollusks from climbing over it.
Copper tape or copper mesh can also be used to create a slug-deterring barrier around a raised bed. Copper deters slugs and snails by reacting with their slime, giving them a small electric shock when they move over it. This method is not 100% effective at keeping slugs out, as it only repels them.
Build an Electric Slug Fence
To build a 100% slug-proof electric fence around your raised bed, you will need:
- 9V battery and connector
- 0.02-inch (0.5mm) galvanized electrical wire
- Staple gun
- Plastic box with a cover for the battery
You will essentially be building an open electrical circuit around the raised bed, with two wires running parallel to each other. When a snail crosses the two wires, it will close the circuit and get a shock, causing it to turn around.
Follow these steps:
- Wrap the wire around the raised bed twice, securing it with staples every few inches. The two wires should run parallel, about 0.8 inches (2cm) apart. Twist the ends of each wire ring together.
- Mount the plastic box that will hold the battery to the side of the raised bed, where the wired meet using a nail, screw, or glue gun. Drill one hold in the top of the box and another in the side.
- Feed the one wire into the top hole and the other into the side hole of the plastic box (this is to prevent the wires touching and short-circuiting) and waterproof the holes with hot glue.
- Install the battery by attaching the two wires to the battery connector and securing the battery inside the plastic box.
Schnexagon is a transparent paint that is designed to repel slugs and snails from greenhouses and raised beds.
When painted onto vertical surfaces, oils and soaps in the paint prevent snails from crawling over them. It can be used on wood, metal, natural stone, clay, terracotta, concrete, and plastic.
The ingredients in the paint are certified organic and are completely biodegradable. It does not contain any poisons or attractant chemicals.
Having raised beds in your garden has many advantages, but keeping slugs and snails out is unfortunately not one of them. Raised beds do, however, make it easier to put up other barriers to protect plants from slugs and snails, like a slug fence, electric slug fence, or copper tape.
Raised beds can also have their sides painted with slug repellent paint, called Schnexagon, which prevents them from being able to stick to vertical surfaces.
Avoid using pesticides or slug bait or pellets to control slug and snail populations in your garden. These products are not only dangerous to wildlife, pets, children, and the environment, but they can actually make slug and snail infestations worse.
Take preventative measures to keep snails and slugs out of your garden, like removing wood, stones, empty pots, or other things they can hide under.