We are in December, with below freezing temperatures at night, but there are still a few snails in the garden. Their continued presence among the greens (chicory, kale, lettuce, rocket) tells about the long season of rain leading up to winter here in north Georgia.
I haven’t seen any serious damage to my plants, so I am not concerned about the snails. To be honest, I am amazed by their persistence in the cold.
If there were very many snails, and a lot of damage to crops, I would set out some organic-approved iron-phosphate bait. The one I have used most recently is called Sluggo, but there are many similar baits, with the same active ingredient, that work.
When I have used the iron-phosphate bait, it was actually for roly-polies, many years ago. For some reason their population had boomed, and roly-polies roiled every square inch of ground in the garden. These critters usually eat decaying organic matter, but there were so many of them that they started eating seedlings in the garden. That was a problem, but the Sluggo iron-phosphate bait for slugs and snails works on roly-polies, too.
It took a couple of years of persistent use of the bait to beat back the roly-polies, but my garden hasn’t been invaded like that again.
The Royal Horticulture Society (RHS), in the UK, where slugs and snails commonly invade gardens and farms and cause a lot of damage, has been studying methods of slug and snail control. Earlier this fall, the BBC reported on an RHS study of home-methods, using things like crushed egg shells, sharp sand, and copper strips to keep the pests away from garden crops.
The study found that none of those things really work, which is sad news for those of us who like to “DIY” as much of our gardening as possible. They had not yet tested beer-traps (beer in shallow saucers, set around the garden, to lure and then drown slugs and snails), so there may be one method left for us to use, other than placing boards in the garden for the pests to hide under, then turning the boards over to pick off the critters by hand to drown or otherwise dispatch.
In another RHS study, effectiveness of iron-phosphate baits and another organic control, nematodes that target slugs and snails, was compared to conventional (chemical) control options. The organic methods did almost as well as the chemicals. Based on my roly-poly experience, I would have guessed this outcome, but it is nice to have that guess confirmed.