This rain we have had (in Melbourne) today will do wonders for gardens already planted, not to mention helping any recently planted seeds and seedings establish themselves for the season ahead. It will, no doubt bring to the surface more than just tiny plants searching for the sun. From their hiding places in virtually any nook or cranny in the garden, snails and slugs will appear, in search of your tasty seedlings and plants, and it is enough to make a hardened gardener weep for their lost effort.
A single snail or slug can wipe out entire plants in a night of feasting, well before your plants have given you any reward. And their approach is rarely considerate, as they often chew off plants at the base, leaving nothing to re-grow after they have moved on to greener, juicier pastures. How is the best way to control these slimy beasties in the home garden?
While there are many snail and slug poisons available, many of them consist of toxic metaldehyde, which despite safety claims from manufacturers, still has stigma attached for many gardeners. That they are manufactured by agri-chemical giants may be deterrent enough for some gardeners, though they are highly effective. Designed to target snails and slugs specifically, and repel household pets and wildlife with colour and taste, they do kill snails and slugs quickly, attracting them directly, and poisoning them with as low an effective dose as possible. If placed in securely fixed, small glass jars at strategic points in the garden, the pellets will neither dissolve into the soil after rain, nor be accessible to larger animals.
Other options include beer. Humble ale is a great way to attract and kill errant garden molluscs (which is what these critters are, zoologically speaking). They are attracted by the yeasty smell, and seem to crawl in, drink their fill, and fall in the beer to drown their sorrows, literally. Placing beer in deep, non porous containers will allow access to the pests, though some form of covering is required to prevent evaporation, dilution by rain or irrigation, or consumption by wayward pets. Larger glass jars, slightly tilted and partially sunken in the ground will do the trick, though the traps should be emptied regularly when successful, as the fermented escargot soup that results can produce something of a pungent aroma.
I have seen many suggestions for snail repellents, such as broken eggshells, sawdust, lime, woodash, coffee grounds, and even powdered mustard. Some of them rely on the idea that the sharpness of the surface will prevent snails from crawling over the barrier to get to your plants. I am yet to see anything that slugs and snails can’t get across by secreting enough slime to smooth their journey. The often repeated story that snails can cross a razor’s blade unharmed are yet to be tested scientifically, though specimens for testing may be donated for scientific purposes. Other barriers intend to dry out the soft bodied creatures, or chemically repel them, but all seem to have little effect after rain, when snails are hunting most actively. Garlic and chilli sprays also seem somewhat ineffective, as I have seen both Garlic (Allium sativa) and whole chilli fruits (Capsicum frutescens) completely obliterated overnight, only a tell-tale silvery trail to point to the culprit.
Hand-picking remains one of the most effective methods. On a rainy night, put on your gumboots and your raincoat, and take a torch out to the garden, and pluck the little suckers up wherever you find them and put them in a container. You can throw them in the bin, or dispose of them as you wish. I always did wonder what people did with mice caught in “humane” traps. Let me know. Searching for their hiding places at other times will also let you catch them unawares, like a vampire in its coffin, and they will hide in all sorts of places. Anything with a smooth surface will be favoured, out of view of potential predators, where they can hide from the sun and conserve their precious bodily fluids. Old plant pots are a particular favourite of these bandits, and you could successfully employ them, upturned, as deliberate traps. I suppose some may find the sensation of slug skin on their own somewhat nauseating, but you could, of course, wear gloves for this exercise.
While you may be able to drastically reduce their numbers, eradication of snails is a near impossibility, as many are functional hermaphrodites, meaning a single individual can self fertilise and lay enough eggs for a new generation. And not all snails are bad news. There are Australian native carnivorous species that feast on the flesh of their imported cousins (most of the garden pests are exotic species). The commonly found species of natives have flat, rounded, smooth shells, usually quite dark in colour. Other native, such as lizards and frogs will also have a field day (or night) chomping down slug fillets or crunchy snail dumplings.
Finally, as permaculture guru Bill Mollison is quoted as saying, “You don’t have a snail problem, you have a duck deficiency”. If you have the space, and the inclination, keeping a duck or two, or some chickens, will reduce the snail and slug population without you lifting a finger, converting them into useful fertiliser, or eggs, or even meat if you are partial. The main issue with letting ducks run around the garden is that they may eat your seedlings too, they aren’t fussy. Though if raised from a young age without being fed vegetable scraps, they are not likely to look at seedlings as food sources directly, but as a hunting ground for tastier morsels. One thing to note, though, as ducks are vented, that is, they excrete all their waste as a kind of slurry in one go, it may be best to find other alternatives, especially if you have a lot of paving