At some point, you’ve probably scoured the internet in the hopes of finding a solution to the slug pest problem. Like most people, you were probably delighted at the plethora of results that claim to offer ‘great’ solutions to try. Maybe you’ve tried every hack and are just about confident with your chosen fix. But are you really sure it works? There seems to be a list of common slug repellent hacks circulating. And it’s about time someone shared why you shouldn’t be using them.
The RHS conducted a research study in 2018 finding that common home slug control remedies, including crushed eggshells, copper tape, pine bark mulch, wool pellets and horticultural grit to be completely ineffective. We decided to put their finding to the test in our own video, to see if these methods really do protect your plants from gastropods.
Do these Slug Control Methods Actually Work?
Read on to find out why these and other common slug repellents don’t really work…
An obvious choice for many people would be to throw some salt on the slugs or around your plants. A straightforward solution, however, with not so simple consequences.
While it may be an obvious answer in the grand scheme of things. It’s also an obvious ‘no-no’ to well-versed gardeners who understand that excessive salt is damaging to plants. The odd sprinkle of salt may have minimal effect to plants initially.
However, over time the more this method is used to deter slugs, an increasing amount of salt will build up within and around the growing medium of the plants and penetrate deeper into the soil with wind and rainfall.
Excess dissolved salt in soil can be very harmful to plants, through osmotic influence. Simply put, instead of taking up water, your plants will be losing it.
Left dehydrated and lacking nutrients.
The other harm to plants salts can cause is through ion toxicity. Plants take up sodium and chloride ions from dissolved salt particles which eventually travel to plant leaves causing burnt leaf edges and scorching.
The Slug Beer Trap
This method goes by the premise of the yeast contents within the beer attracting the slugs. With the hopes of the slugs becoming intoxicated after drinking it and therefore drowning in the liquid trap.
One of the most common slug deterrents hack you’ve probably come across is the old crushed eggshells trick! This method supposedly works with the belief that when an uncooked egg’s shell is crushed. The edges are sharp enough to hurt slugs should they decided to slide over them.
Copper tape is a method subject to much scepticism when it comes to slug control. The general claim is that this metal reacts with the slime produced by gastropods (slugs and snails) to create an electric signal that gives them an electric shock.
If you were going to question any slug control method, then this is definitely the one. Many gardeners who follow this method are putting a lot of faith into a claim that technically isn’t backed up with scientific evidence.
While there’s also that copper tape has repelled slugs under lab conditions, nobody is gardening under lab conditions.
Within our own tests, copper tape proved ineffective at repelling slugs and there were no signs of shock or unpleasant feelings while observing them.
Wool pellets are not to be confused with slug pellets. Although they’re similar in design, they work differently. Wool pellets are made of 100% raw compressed sheep’s wool that is compacted into small pellets. The idea behind this method is that wool pellets will deter slugs and snails by absorbing the mucus they produce.
The problem with wool pellets is that a little rainfall makes them completely useless. Considering slugs are most active during and after a period of rainfall, this isn’t ideal. Especially in a climate of everchanging and unpredictable weather like the UK.
Several other problems with this method include the traces of salt that wool pellets might contain washing into the soil after rain. Which as explained previously, can have damaging effects to plant growth.
Gardeners have also claimed that rather than deterring slugs, wool pellets, in fact, have acted as a soft cushioned mattress for slugs. Giving them a place to rest and make a home of while munching on their plants.
Lastly, we can’t forget to mention how notorious wool pellets are for their awful smell.
Don’t ever open a packet of these inside your home!
Pine Bark Mulch
There are two main reasons behind using pine bark mulch to control slugs and snails. Gastropods do not like to travel across extremely dry surfaces because they will lose essential mucus.
However, much like wool pellets, pine bark mulch only serves to encourage slugs to travel towards your plants after contact with rain and moisture.
Even without rainfall, the coarsest of bark mulch clippings fail as plant slug protection because they naturally trap moisture for plants.
Creating the ultimate haven for slug and snails to hide, lay their eggs and destroy your crops.
This method supposedly works with the idea that the harsh texture of finely crushed horticultural grit repels slugs from travelling over it.
Horticultural grit is probably one of the simplest methods, aside from salt. However, much like every other method with claims that harsh surfaces will cut and damage slugs to prevent them from travelling on its surface.
It forgets that these slimy creatures produce their mucus with the sole purpose of being able to move across a range of harsh surfaces.
In fact, we recently found a video that shows slugs effortlessly gliding across the surface of sharp knife edges. So methods like this and crush eggshells don’t really stand a chance.
Finally, we have good old, or should we say bad old slug pellets. We wouldn’t call these a hack, but they are a very well-known method of slug pest control that as of June 2019 will be banned from sale and spring 2020, banned for gardeners to use.
You might want to read up on why slug pellets are dangerous for children, pets and wildlife.