Slug-proofing experiments

For the last few months, I’ve been experimenting with various ways in which to try to control the slug population or at least what they are eating. I have to say that single methods don’t often work on their own, so I think it has to be a multi-pronged attack! This is what I have tried:

• Electric fence: a galvanised wire was wrapped twice around a raised bed and connected to a 9 volt battery. It should be enough to discourage the slugs but will not harm them. This works quite well, but the wires were quite stiff and needed to be a centimetre or so apart, so smaller slugs can still get through. The battery also loses charge quite quickly so needs to be checked and replaced frequently.

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• Copper wire: a bit of copper wire was just wound around the stem of a Daphne bholua which was being attacked and eaten pretty mercilessly. The copper was just a bit of old wiring, loosely wrapped around the woody part of the stem. This has worked very well and the young leaves a bit higher up have stopped being attacked.
• Crushed egg shells: washed and crushed egg shells have been placed in a circle around plants. This has worked reasonably well. The egg shell seems to keep some of the slugs away, but not all, but it at least gives the plant a bit of a chance to grow and get stronger. The only thing is that you do need quite a lot of eggs to create a good barrier.

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• Sandpaper: coarse sand paper was fitted as a sort of collar around the stems of young plants. This didn’t really work at all.
• Hair: yup, I put my own hair around plants. After cutting my hair, I put the cuttings around the plants, right up to the stem in quite a thick layer. Weirdly, this has worked really well, but I’m not entirely sure why. If my hair grew a bit quicker, I’d do this more. Although I cannot tell you how bizarre it feels to be looking at your own hair on the ground around a plant.
• Mesh: I put a tube of gutter guard mesh around young plants to protect them from the larger slugs. The mesh holes are maybe 0.5cm in size. I tried doubling the layers of the mesh to make the holes smaller. This didn’t work either.
• Cloches: made of milk bottles, cut around the middle and with the lid off to allow ventilation. I think these worked ok, although I found some plant damage and also caught a few slugs around the lid openings preparing an assault. I modified the design to have two bottles with one making a kind of skirt of overhang to make it more difficult for the slugs to get to the opening. This worked better although the plants themselves didn’t seem too happy under cover, so I abandoned this method.

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• Bran: I put wheat bran in circles around plants and also in shallow saucers (the bases of plastic milk bottles cut off) in places that I know the slugs travel. There was definitely less damage to the plants initially, but the effect stopped or slowed down after a couple of weeks. It may be that the bran had got wet and was less appealing or that the slugs got bored of being healthy. I’ve read that the slugs get bloated on the bran and are unable to get back to their hidey-holes by the morning, but that wasn’t the case for me. I think that the bran was just a distraction, it does not seem to have done anything else. It was quite cheap though, and worked well for a while.
• Copper tape and grease around pots: this has worked very well, but only works on pots and not for plants in the ground. The copper looks nicer than the grease, which I put on in a very thick band around the pot and which now has flies and dirt stuck to it.
• Beer traps: These caught a large number initially, of smaller slugs. They became less and less effective and I wondered whether this was because of the smell of the beer was being overtaken by the smell of slug. Even when I cleaned the traps and replaced the beer, these never became as effective again. I think that they learned to avoid them. I also found that most of the slugs in the traps were not dead, just a bit drunk, and that the larger slugs could just put their heads in the beer to drink it and then go on their way.
• Hand removal/night-time hunting: I went out at night, maybe twice a week and removed every slug I could find. This definitely seems to help restrict plant damage. In the spring, I found far more slugs each time I went out, and these slugs were of medium size. Now, in the summer, I have been finding fewer slugs but these are much larger and heavier. I just hope I’ve caught them before they’ve had a chance to lay eggs. However, I’ve just started noticing some really tiny slugs too, so I think that these have only recently hatched.
• Wool pellets: I used these last year, and they didn’t work at all for me. A pity because I really wanted them to work.
• Nematodes: Also used last year, I purchased fresh nematodes and followed the usage instructions to the letter. They made no noticable difference to the number of slugs.

Did I miss anything out, or do you recommend any other ways of deterring slugs? Let me know in the comments!