One of the most annoying and persistant pests for gardeners, slugs consistently rank highest in assessments of garden foes.
They devour priceless plants’ new growth, destroy seedlings over night, and eat holes of unusual shapes in leaves, stems, blossoms, tubers, bulbs, and potatoes—leaving behind trails of silvery slime.
Although slugs are active throughout the year, they pose a special threat in the spring, when there is an abundance of tender foliage for them to consume. Most of the time, they are active after dark, especially in warm, humid weather. To prevent drying out in hot, dry weather, they burrow themselves into the ground or hide in cool, shadowy areas.
In Australia, there are more than forty species of slugs. However, not all slugs consume living plants; a lot of the larger ones consume dead or rotting vegetation.
There will inevitably be losses to slugs despite your best efforts. Recognize that there will always be slugs in your garden and come up with solutions to deal with them.
Prioritize protecting the most susceptible plants first. These include all seedlings, new growth on the majority of herbaceous plants, and all sections of particularly fragile plants like dahlias, hostas, and delphiniums. Make sure there isn’t a “bridge” of leaves connecting the plants in your potted plants, as this is a common route for slugs to move from one pot to the next.
Grow more than you need to ensure that you have some crops left over after a slug assault, and sow extra seeds so you have seedlings waiting in the wings to replace any that are eaten by slugs. To minimize damage, add many of slug-resistant plants (see out our list below).
How to control slugs in the garden
Establish a thriving ecosystem
The best way to keep slugs out of your garden is to establish a thriving ecology. To attract birds like blackbirds and thrushes, who eat slugs (and snails), plant hedges, bushes (particularly those with berries), and trees. This will create a multitude of habitats for slug predators. A wildlife pond is a wonderful addition to your landscape, provided you have enough space for it. The toads, frogs, and newts that use it will eat slugs. Slats attract slow worms, which consume a lot of slugs, when they are laid down. To attract wildlife to your garden, consider making a small opening in your fence that allows frogs, toads, slow worms, and other species—like hedgehogs—to freely move between your plot and those of your neighbors.
Since slugs typically target plants that are already weak, plants grown in good soil are far more resilient to slug harm. Thus, to promote healthy soil, mulch your garden with well-rotted manure, handmade compost, or composted green waste. If you don’t currently make your own compost, have a look at our in-depth how-to guide, which also features a list of the top compost bins available for purchase.
Build a slug-free area of the garden
Although you can’t completely eradicate slugs from your garden, you can designate a small area that you want to remain slug-free. The region where young plants and seedlings are most susceptible to slug attacks should be given priority, such as the area inside and surrounding a raised bed or cold frame.
Before you fill your pots with compost, cover the bottom of them with fabric or mesh to keep slugs out of them. Wait to sow seedlings outside until they are a respectable size; this will increase their resistance to slug damage. Avoid overfeeding young plants since this can lead to lush, green growth that slugs adore.
Build a slug zone in the garden
One of the most common methods for controlling slugs is to walk outside after midnight with a torch and a bucket of salt water, ready to pick them off plants. The ideal time to accomplish this is two hours after sunset, which implies late summer evenings. For this task, you could find it more convenient to use a pair of gloves.
To make the task easier, use anything slugs are drawn to, such as dry cat food, bread rolls, oats, or bran, to purposefully draw them to a dark, shaded spot. Swoop in and pick them up at night as they gather for a feed.
As an alternative, look for slugs’ daytime hiding spots. They hide behind plant pots, pot saucers, garden furniture, and tread boards on the vegetable plot, among other cold, dark, and moist places.
The time-tested method of employing bricks or grapefruit peels works well; slugs hide beneath them during the day. Regularly look under these areas and get rid of any slugs you find. On borders, slugs can also be found hiding beneath decaying plant matter. Remove it and place it in the compost pile, where the slugs will carry on with the composting process.
Additionally, keep an eye out for slug egg clusters in the spring and fall. Slugs can lay up to 50 eggs at a time. A few millimeters in diameter, they resemble white balls that are translucent. They are frequently discovered in damp soil pockets, beneath plant pots, under stones, and in other chilly, dark areas. Squash them as soon as you see them, or leave them out for the birds. Rake the soil surface in the spring to reveal them and leave them for birds and centipedes to enjoy.
While salt does kill slugs, plants are also harmed by it.
Put organic slug pellets to use.
Metaldehyde-containing slug pellets not only kill the slugs but also the birds and hedgehogs that eat them.
Organic gardeners have approved the use of pellets derived from ferric phosphate, which are equally effective but appear to be less damaging to wildlife. As quickly as possible, distribute the pellets around the soil before the sensitive new growth shows.
However, keep in mind that if you disperse them widely, eventually fewer predators will visit your garden to feed on the slugs, forcing you to rely more on pellets. Thus, make use of the pellets.
Water in a biological control
Growing numbers of organic gardeners are using biological pest treatments that include tiny nematodes. These bacterium-infected slugs eventually die. In the evenings, starting in spring, when the soil is damp and warm (it should be at least 5°C), water the soil.
Throughout the growth season, multiple treatments are required because it is effective for approximately six weeks. Treating your entire garden in this manner is impracticable, so give important sections like the vegetable patch or a raised bed priority.
Water your plants first thing in the morning
This guarantees that by dusk, when slugs are most active, the earth will have dried up. A slug highway can form between plants at night when the soil is wet.
Try copper around the base of your plants
Slugs are deterred by copper rings, which give off an “electric shock” when a slug tries to cross them and is forced back. Place rings around plants that are susceptible, such hostas; bury them deeply because slugs may get to the plant from underneath.
Additionally, some gardeners swear by wrapping copper tape around pot rims, despite an RHS trial revealing this to be unsuccessful.
Try plant cloches to protect your seedlings from slugs
Plant cloches will cover your delicate little seedling and protect your growing little plant from slugs, snails and other pesky little bugs that could nibble away at your growing plant or herb.
Simply buy a garden cloche, place it on top of the growing seedling and watch as your plant grows protected from both the dangers of insects and weather.
Spread bran around the plant pot to stop slugs
Slugs will devour bran because they adore it. After that, they grow bloated and dehydrated and are unable to return to their hiding spots, which makes them prime prey for birds.
Use a garlic drench, a slimy barrier, or a sharp mulch to deter slugs
Slugs find it difficult to go over prickly or pointy surfaces. Ash, bark, cat litter, cocoa chips, sawdust, sand, and horticultural grit were among the commonly used barriers. Try using coffee grounds or wool pellets as well. Remember that most slugs live in the soil, not on the surface, and that these require frequent topping off. While their research is ongoing, a recent RHS trial showed several of these treatments were ineffective.
A greasy, slimy barrier like petroleum jelly or WD40 was also suggested by some experienced gardeners; generously coat the rims of pots and seed trays with it. Another suggestion was to use double-sided sticky tape that was heavily coated with salt and affixed to the rims of pots.
It’s also reported that the smell of garlic repels slugs. Douse valuable plants with garlic at night, making sure the leaves are well coated. Use frequently, particularly after rain.
Can you spare some beer for a slug beer trap?
Use cheap beer to make a slug trap; slugs will be drawn to the scent. Place a beer trap or container in the ground, making sure that the rim is just above the earth. Pour in half of the beer and cover loosely to prevent intruders from dropping in.
Empty the trap and check frequently. The ideal location for the trap is near the edge of a vegetable patch or border; if it is within, the slugs will eat your plants as they make their way to the trap. Another idea from a reader was to attract additional slugs by leaving a few dead ones at the bottom.
