How to Control Slugs and Snails in your Organic Garden

The most frequent questions I get regarding organic gardening concern control of disease and insects. My answer tends to frustrate people, because I believe that the most important thing you can do to ensure a pest-free garden is to build healthy soil that produces healthy plants. We live in an imperfect world, of course, so there will surely be times that you want a few strategies to control slugs and snails in your organic garden.

We have an area of our garden that tends to hold some water after a rain. And that tends to be an area where slugs or snails can be a problem.

Slugs and snails are similar, except that snails contain a shell. Both excrete slime, and leave a trail of slime as they travel. During the day, slugs and snails hide in damp places – under rocks, or logs, mulch, or even planters. And they both come out to feed at night.

These pests can decimate young seedlings overnight, but also feed on mature cabbage and other plants with tender leaves like lettuce, tomatoes, or peppers. They also love the hosta in our garden.

Preventing Slug and Snail Damage

Slugs hide in decaying plant matter, so keeping debris away from the plants that these mollusks love may help.

Because they love moisture, it is best practice to only water in the morning, allowing the plants to dry by evening (this practice also helps to prevent disease in the garden).

Slugs will generally avoid crossing rough surfaces, so surrounding the base of the plant with something rough is a great deterrent. Circles of metal window screening work well. Other helpful ideas include coffee grounds, crushed eggshells, gravel, or wood ashes.

I have found that hand picking slugs or snails is a very effective control. During the day look for them in moist areas under rocks, etc. In the evening, take a flashlight out to the garden and hand pick the mollusks from your garden plants. If you have chickens or ducks they will love the snack. Otherwise, place them in a jar of soapy water to get rid of them.

What about copper, beer, or yeast to deter or kill slugs?

Many say that slugs will receive a mild shock when they crawl over uncoated copper tape. I have never tried this but have seen videos that seem to debunk this – the slugs crawl right over the tape and keep moving forward.

I personally have not have much success with beer, but others swear by it, and it’s certainly worth a try in your garden. Place a dish of beer at ground level near plants that are being attacked. It attracts the slugs or snails, and they crawl in and drown. You need to replace the beer each evening.

I have also tried leaving out a watery yeast and flour mix, but again, have not had success attracting slugs with this concoction.

Organic Products that Control Slugs or Snails

It is always best to start with preventive measures, or hand picking to control snails and slugs. Only then is it advised to move on to organic products.

The two best organic products for controlling these pests are diatomaceous earth and iron phosphate.

Diatomaceous earth is made from diatoms and is a soft, white powder that is microscopically sharp. As insects crawl over the powder, their bodies are pierced, resulting in dehydration and death. It is generally more effective on insects with hard exoskeletons, but can be somewhat effective with slugs.

Cautions: Be careful when applying diatomaceous earth as it can damage lungs if breathed in. In addition, it is best to apply this in the late evening when bees are not active to avoid harming them. Do not apply to any plant that is flowering so as not to harm other beneficial insects.

Iron Phosphate causes slugs and snails to stop feeding. It is quite effective, more so than diatomaceous earth.

Cautions: Overuse of iron phosphate can cause high iron or phosphate levels in soil leading to deficiencies that can cause stunted plants.

Recommended Reading: The Organic Gardener’s Handbook of Natural Pest and Disease Control by Bradley, Ellis, and Martin

Other Organic Gardening Posts You’ll Love

Preventing Blossom End Rot in Tomatoes

Preventing Late Blight

How to Build a Lasagna Garden

Guide to Raised Bed Gardening

To learn how to build a garden that builds healthy soil, be sure to check out my eBook The Art of Gardening: Building Your Soil. You really can become a better gardener, and you really can grow healthy, nourishing produce. It’s all about the soil! Click here to buy now.