How to control slugs
I absolutely loathe slugs. They are a huge pest in my strawberry patch, and a minor pest in my annual garden. I mulch my garden with either shredded hardwood or straw, and I definitely have more slug problems from mulching. Having said that, the benefits of mulching far outweigh the slugs. I have tried quite a few cultural and home remedies.
1. Beer traps
Save your tuna cans, clean them out, then set them in the soil so the top of the can is at soil level. Then fill with beer. The yeast in the beer attracts the slugs. They fall in and drown in the alcohol. I used this method with moderate success last year, but to be honest it’s kind of expensive, unless you have a free source of outdated beer. If you can get free past due date beer, this is a decent method. You just need to install a lot of traps, at least one per 10 square feet. Hence the reason free beer is important. Also, I think tuna cans are as shallow as you can use. I tried old mason jar lids, because I would need a lot less beer. I watched a slug fall in it and crawl right back out. The walls weren’t steep and deep enough.
Cost: High, if you are buying the beer
Effectiveness: Moderate, but you need a lot of traps
Labor: Moderate, you need to install the traps then change out the beer every couple of days
2. Placing down plywood next to affected areas
You can place sheets of plywood down, and during the day the slugs will gravitate to the wet area under the plywood, then you can simply lift the plywood each day and kill all the slugs. Well in theory that sounds good, but I got very few slugs with this method. Ultimately, it wasn’t worth the effort.
Cost: None if have some old plywood laying around.
Labor: Moderate, you do need to check under the boards each day.
3. Copper wire
I know of some gardeners that put copper wire or ribbon around vulnerable areas of their garden. Apparently, it gives the slugs an electric charge. I have never tried this, but given the cost of copper, I can’t imagine this is a cost effective solution.
Labor: High (Imagine putting copper ribbon all around your garden)
Some gardeners will take their egg shells clean them, crush them up, and place them around vulnerable areas. I have tons of eggshells, but I am skeptical of the effectiveness of this.
Effectiveness: I don’t know.
Labor: High. I think it would be a pain to clean, break apart, and spread out enough eggshells to make a difference.
5. Diatomaceous Earth
Similar to the eggshell idea, if you sprinkle this around, when the slugs go through the DE, their bodies are ripped open by the jagged fossils. This is not a bad idea, but it gets expensive, because you have to reapply after rains.
Labor: Moderate (You don’t have to clean and grind up the DE, but you do have to reapply after rains)
6. Sluggo Organic Bait Control
Sluggo bait is iron phosphate, so it is safe to apply to your garden without fear of damage to your ecosystem. This organic control is very effective.
Effectiveness: I had great slug control with this product.
It is important to not irrigate in the evening. You are creating a slug sanctuary if you do so.