I am often asked about damage to a plant where the client has not seen any pests. Sometimes this is caused by slugs and snails that often come out at night or early in the morning eating plants.
Damage from slugs and snails can be reduced by changing the way you water. Since they require moist soil, reducing watering where possible can reduce their numbers. It is common for landscapes to be overwatered. Most plants in most growing conditions do not need to be watered daily or even every other day.
Some other control types:
Beer or a mixture of honey or molasses with baker’s yeast placed in a container. I find this works best if placed in a bottle which is then angled to reduce the chance of rain or sprinklers diluting the mix. These will need to be checked frequently due to evaporation.
Iron phosphate slug baits work very well and are not harmful to people, pets, birds or wildlife. Sluggo and Scar-Go! They are a couple of brands that I have used.
Nutribiotic (grapefruit seed extract) mixed 5 drops per cup of warm water. Spray on slugs and snails. Nutribiotic can also help if sprayed around plants to form a barrier.
After eating cantaloupe, watermelon, or grapefruit, place the skin face down outside with the rim up. Go outside later and you should find plenty of slugs or snails inside.
Barriers can also reduce damage from slugs and snails. Small bits of hair (people or pet hair), crushed eggshells, sharp sand (not play sand) are all nasty to them and can protect your plants. Diatomaceous earth (also called DE) works as a barrier and a killer as long as it doesn’t get wet. Be sure to buy the garden type (not the pool type) and read the label to make sure it’s pure DE.
Copper sheeting at least 2″ wide or copper wires spaced 2″ apart can also provide a barrier, but is generally easiest to install in planters, planters, or raised garden beds. A Chore Boy could also be detached for this use.
Mint, lavender, and sage are herbs that are supposed to repel slugs and snails. I haven’t tried this, but I did find a snail in my bottle of spearmint, so I’m wondering if mint is a repellent? The mint will repel rodents and ants. You can place a few leaves or an essential oil spray in water from one or both around your plants and see what happens.
Ground cinnamon repels some pests and I have heard of success as a slug repellent.
Some people have had success with coffee grounds around the plants. That would probably be great in my area where the soil is alkaline, but if your soil is acidic, be careful to acidify it further, don’t go overboard with the coffee grounds.
Tending your garden organically allows the natural predators of slugs and snails to help you. Some birds (including ducks and chickens), ground beetles, snakes, lizards, turtles, and frogs are some of the natural predators of slugs and snails, so help them by learning how to attract them and using only fertilizers. and organic pesticides. If you have chickens or ducks, you may want to let them roam your garden or landscape from time to time to clean up for you.