My biggest big sister recently sent me a book entitled ‘100 Ways to Kill a Slug’. She knows I am a sucker for any horticultural literature. That said, I wasn’t quite sure what to make of another literary gift from a good family friend called ‘100 Plants that won’t die in your garden’… but always up for a challenge, me.
As the weather warms, slugs become more of a pest. They are frustratingly robust against cold weather, as they can over-winter as either eggs, juveniles or adults. Just as you are thinking of starting to sow your first succession of spinach and salad leaves, and planting out anything tender, so too should you be considering how to protect them from slugs and snails. Here are some of the one-hundred methods that I am more familiar with.
Beer traps
To now, this has been the most effective slug-control method for me; sink a jam jar of beer into the soil near your young leafy crops to attract and intoxicate the slugs. Empty the traps by straining through a flower pot lined with kitchen paper, and throw the slugs in the green waste bin. In my experience, slugs have a preference for real ale over Jamaican Red Stripe.
Parasitic nematodes
Last week, at Cheadle College, we watered around our raised beds with some ‘Nemaslug’, in order to tick the ‘Biological Control’ box for our Level 2 assessment. First of all, we cut away all of the long grass immediately surrounding the raised beds, to expose the soil. This is the place where slugs are known to enjoy hiding – where the soil meets the timbers – so the target for nematode-watering.
The nematodes are parasitic worms that are mixed into the water. Once applied, they enter the slugs and release bacteria that stop the slugs feeding and they die, generally whilst still underground. You need to keep the packet sealed and refrigerated until use, and then read the instructions carefully about the required quantities and dilution rates. Despite being miniscule, the nematodes still blocked the watering can roses, so use a course rose. The treatment lasts about six weeks, and is not harmful to children, pets or wildlife.
Cultural control
Apparently, slugs dislike the strong smell of mint, chives, garlic, geraniums, foxgloves and fennel, so planting these around your garden will help deter them. Also, consider gardening in a way that attracts beneficial organisms that enjoy eating slugs such as frogs and hedgehogs. Possibly one for another year now, but hoeing the ground in early spring can also expose the white spherical eggs, which are then picked off by birds.
Other methods
· Go out in the dark with a head torch, particularly after rain, and collect up the critters by hand;
· Place empty grapefruit skins, outer-skin side up, on the grass or beds. In the morning, they will apparently be full of slugs, throw the skins plus slugs into the green bins;
· Sprinkle cut hair or pet hair around the base of your plants;
· Torch the slugs with a weed-burner (!);
· Barriers made of copper tape, soot, diatomaceous earth, or sprinklings of dry grit and sand.
Quite a choice of battle strategies here! Let me know what’s worked for you.
Slugs - not the gardener’s best friends