Naturally Get Rid of Those Garden Slugs
Okay spring is here and I am already seeing the slimy paths of slugs left behind on my garden plants. This doesn’t bode well for the survival of my plants. But what can I do to prevent the wasteland that’s about to come from the invasion of those little snot monsters? Slugs use file-like mouthparts (called radula) to rasp and chew plant tissue.
Slugs are generally active at night when it's cool and damp, although they may be seen during the day in cool, shaded sites. Warm, dry conditions are less favorable to them. Generally, slugs do not bother plants that grow in full sun.
Why Are Slugs in My Garden?
Slugs feed on ornamental plants that grow in partial to full shade and on fruits and vegetables. Plants they are likely to damage include bellflower (Campanula), larkspur (Delphinium), plantain lily (Hosta), daylily (Hemerocallis), Dahlia, lungwort (Pulmonaria), strawberries, basil, beans, cabbage and lettuce.
Ground covers like spotted dead nettle (Lamium maculatum) create an inviting slug habitat by shading soil and keeping it cool and moist. The risk of slug feeding is higher during times of cloudy and rainy weather.
But first, not all slugs are here to make your gardening season miserable! The green cellar slug likes to hang out on compost heaps and also enjoy a diet of mould and algae.
How To Control Slugs
Look for them and control them naturally
Look for slugs under plants where it is shady, cool and protected. Slime trails are signs of slug activity. In the evening, use a flashlight to locate slugs.
There are many types of animals that feed on slugs: beetles (ground beetles, rove beetles, fireflies), toads, snakes, turtles, shrews, ducks, starlings and other birds. Birds, frogs, toads, Devils coach-horse beetles and hedgehogs all like to snack on slugs. Ducks and some hens enjoy snacking on them too, if you’re lucky enough to have them. Turning over soil will expose the slugs to birds in dry weather. Encourage these natural enemies when practical in your garden.
‘Phasmarhabditis hermaphrodite’ also known as NemaSlug are available online that can be watered onto plants. They’re supposed to be very effective but the downside is that they’re quite pricey and will have to be re-applied after six weeks or so.
Handpick slugs off plants by looking for slugs on leaf surfaces and underneath leaves as well as under rocks and debris.
Drown slugs in soapy water or crush them. Set out several flat boards, shingles or damp newspapers. Set out beer traps that attract the slugs.
Copper has been shown to deter slugs by reacting with their mucous, which gives slugs something like an electrical shock. Copper foil or bands may be used horizontally or vertically, but they must be wide enough to accommodate the whole slug. Caution: The sharp edges of some products may cause safety problems, especially for young children.
Diatomaceous earth (tiny fossilized skeletons of ancient aquatic diatoms) is coarse and can scratch up slugs. It is most effective when used in dry conditions and has little effect when it absorbs moisture. It is generally not an effective slug deterrent.
Slugs and snails do not like coffee. Sprinkling coffee grounds around plant bases will act as a repellent, as does filling a spray with cold, strong coffee and spraying slugs. That said, coffee grinds are best added to the compost heap as their slow release nutrients will help to improve the soil in the heap.
Discourage slugs by creating lighter, drier conditions.
Prune lower tree branches and shrubs to allow more sunlight to reach plants and soil.
Divide or thin plants to improve air circulation, allowing the soil surface to dry out.
Stake plants and prune lower leaves to raise plants off the soil and away from slugs.
If planting in rows, make plant rows narrow (12 to 18 inches wide).
If soil is constantly damp, improve drainage by amending soil with compost.
While chopped leaves make an excellent mulch, too much can encourage slug habitat. Remove and compost extra leaves in spring.
Remove or relocate materials where slugs hide such as containers, boards, pavers and flat stones.
Grow a water-wise garden
Slugs are active in the evening; water plants in the morning so water is absorbed and plants dry.
Water the root zone at the base of the plant.
Avoid overhead watering.
Water by hand or use drip irrigation or soaker hoses.
Do not water leaves, flowers, fruit or vegetables.
Plants for drier conditions and full sun (6+ hours of sun):
Perennials: yarrow (Achillea), wormwood (Artemisia), milkweed (Asclepias species), asters, coneflowers (Echinacea, Rudbeckia), hardy mums (Dendranthema species), ornamental grasses, iris, Shasta daisy (Leucanthum superbum), gayfeather (Liatris), lily (Lilium), bee balm (Monarda), phlox (Phlox maculata, I), balloon flower (Platycodon), sage (Salvia), stonecrop (Sedum), painted daisy (Tanacetum), false lupine (Thermopsis), tulips, daffodils, crocus and other early spring bulbs
Ornamental grasses: blue oats grama (Bouteloua), reedgrass (Calamagrotis), bloodgrass (Imperata), moor grass (Molinia), switchgrass (Panicum), fountaingrass (Pennisetum), prairie dropseed (Sporobolus heterolepis)
Grow shade plants that slugs do not like
For full shade (6+ hours of shade):
Perennials: Creeping phlox (Phlox stolonifera), woodland phlox (Phlox divaricata), bleeding heart (Dicentra)
Ferns
Ornamental grasses: tufted hairgrass (Deschampsia), hakone grass (Hakonechloa)
Sedges: Gray’s sedge (Carex grayi), Pennsylvania sedge (C. pensylvanica), Japanese sedge (C. morrowii), plantain sedge (C. plantaginea)
For light to part shade (3-4 hrs, dappled sunlight):
Perennials: Monkshood (Aconitum), lady’s mantle (Alchemilla), columbine (Aquilegia), swamp milkweed (Asclepias incarnate), false spirea (Astilbe), turtlehead (Chelone), bugbane / snakeroot (Actaea), pinks (Dianthus), spurge (Euphorbia), cranesbill (Geranium), coral bells (Heuchera), catmint (Nepeta), evening primrose / sundrops (Oenothera), spiderwort (Tradescantia)
Ornamental grasses: oatgrass (Helictotrichon), reedgrass (Calamagrostis), blue fescue (Festuca glauca)
Sedges: blue sedge (Carex flacca), palm sedge (Carex muskingumensis)
Clematis: Grow this flowering vine on a trellis or fence in full sun, but with the base of the plant shaded and cool.
Slugs do not typically damage trees and shrubs.
