How to Spot the Difference

Slugs and snails are notorious leaf chewers in vegetable, flower, and fruit gardens. Both belong to the animal family called gastropods and are close relatives of mollusks like clams and mussels. They attach themselves to foliage and fruits leaving large irregular holes and shiny trails behind.

Both generally feed at night and thrive in dark, damp environments. There are some notable differences between snails versus slugs that can help you figure out which one is causing damage and how to prevent it.

What Is a Snail?

The snail most commonly found in vegetable and flower gardens is the brown garden snail, (Cornu aspersum). It is a soft-bodied animal that moves by a single ‘foot’ kept constantly moist by the production of mucous. This helps the snail glide along surfaces and, along with snail waste, leaves behind a silvery trail.

Snails carry a spiral shell banded in chestnut brown with yellow streaks or flecks. Snails possess both female and male reproductive organs and a single individual can produce offspring, although they can also mate.

Snails feed at night and are indiscriminate about food sources, sampling almost anything available within a short distance.

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What Is a Slug?

Slugs are also found all over the globe thriving in fresh and salt water and on land. Milky Garden slugs, (Deroceras reticulatum), are likely the culprits causing damage in your flower and vegetable gardens.

Like the brown garden snail, this slug feeds on a wide array of vegetables and ornamentals and is particularly attracted to corn, lettuce beans, and hostas. The smallest form is a small at 1 1/2 to 2 inches long and the great gray garden slug measures 4 to 8 inches.

These creatures are light brown to gray with larger forms sometimes bearing spots. The upper part of the torso features a raised, ridged mantle.

Slugs also move by using a moist ‘foot’ to help propel them across surfaces. They do not have shells.

Snail vs. Slug: Key Differences

All terrestrial slugs evolved from land snails by losing their shells and continue to share a number of snail habits and behaviors.

Both species shelter during the day in soil cracks or underneath leaf litter, rocks, and other ground surface materials. Many species are hermaphrodites and reproduce by laying eggs.

They prefer to feed in cool, dark conditions but are sometimes seen during the day in overcast or rainy weather. Both are sensitive to drying heat and keep their soft bodies moist by producing mucous.

Here are a few ways to tell the difference between snails and slugs.

Brown Garden Snail

• Carry a shell that protects them from drying out.
• Most active during summer months.
• A wide range of food sources including vegetables, fruit trees, cereal grains, shrubs, and flowers.
• Grow to a standard range in size of up to 3 inches long with a shell that measures up to 1 3/4 inches in diameter.
• Lay six clutches of an average of 80 eggs yearly during winter months.
• Lifespan of two to five years.

Milky Garden Slug

• Do not have a shell which makes them vulnerable to drying out.
• Most active in spring and autumn.
• Diet consists mostly of vegetables and flowers.
• May be different sizes depending on the species.
• Lay eggs year-round in clutches of 40 (average) with the greatest activity in spring and autumn.
• Lifespan of one year.

How These Pests Impact Your Garden

Slugs and snails are attracted to plants with lush foliage and fruits that grow close to the ground such as strawberries and melons. Young plants and seedlings are particularly vulnerable to damage from slugs which are more active in spring during periods of early garden growth.

Mature plants may suffer in appearance and usually survive feeding, but seedlings and succulent types of plants can become defoliated and die during periods of heavy feeding which also adversely impacts yields of fruits and some vegetables.

If you see just a few of these animals in your gardens there is probably no need to panic. Snails and slugs also feed on plant debris, dead insects, and dead worms which breaks down garden waste into beneficial compost.

They attract predatory reptiles and birds including toads, turtles, and snakes which help control other pest populations in the garden.

What to Do About Slugs or Snails

For home gardeners, slugs are more destructive leaving flower foliage, strawberry and vegetable plants ragged and unsightly.

Snails are found in smaller numbers and are a bigger problem for commercial nurseries and fruit growers where infestations cause significant damage to citrus crops in Florida and California. In large numbers, they become a nuisance around a home.

There are several steps you can take to discourage snails and slugs or get rid of them around your home and gardens.

• Practice good garden hygiene and remove garden debris at the end of the growing season.
• Remove any object on the ground that provides a dark, damp place for them to hide under.
• Or you can place a few boards around your gardens, check each morning, and remove any slugs or snails found underneath.
• Diatomaceous earth, sand, coffee grounds, and ashes are either toxic or desiccating, causing them to dry up and die. A vinegar spray also has a drying effect but use it carefully as too much alters soil pH.
• A shallow dish filled with beer or sugar water attracts the animals. Bury the dish so the lip is even with the soil surface. They can’t get out of the dish and drown.
• Snails and slugs avoid the sharp edges of broken eggshells which pierce their soft bodies.
• Certain flowering plants have a fragrance disagreeable to snails and slugs. These include geraniums, ferns, mints, lavender, and rosemary.
• They are sensitive to copper which causes an electric shock in their soft bodies when they contact the mineral.
• As a last resort, commercial snail bait can be used. Be aware that these chemical formulas may damage other wildlife and beneficial insects.