copper tape has some effect to repell slugs and snails, but it’s effect is mild.
We’ve tested copper in our UK based slug and snail laboratory to determine its role in repelling slugs and snails and preventing damage to your plants. We experimented with various popular forms—copper tape, copper mesh, and copper pipe (see below)—to see if one was more effective than the others and whether any of them could serve as a natural slug deterrent.
Our results show that copper is not reliable for protecting garden plants. However, it does help reduce slug and snail damage to some extent, as it appears to have a mild repellent effect and below is how we rank copper overall taking into account 4 factors including immpasibility, enviromental impact, cost- effectiveness and maintanence required. For further information and the breakdown of that score is further down the page.
Also, to back up our thoughts that copper isn’t very reliable here’s what the RHS had to say: “A recent RHS study in a garden-realistic scenario found no reduction in slug damage from barriers made of copper tape, bark mulch, eggshells, sharp grit, or wool pellets (Royal Horticultural Society, 2023).”
In this blog post, we’ve included the full video of two of our experiments at the bottom if you want to see the results for yourself. We’ve also added a link here: 3 Steps to a Slug-Free Guide—which takes you to our comprehensive guide to slug control – for gardeners who want this problem fixed once and for all. This guide covers everything you need to know about barriers in Step 2, along with other effective methods for managing slugs and snails.
Copper can be used as a barrier or repellent for both potted plants and those planted directly in the ground. However, we believe there are more effective barrier options available, and copper would never be our first choice as a deterrent. First, let’s explain why it wouldn’t be our top recommendation for protecting potted plants or those in the ground and then we’ll go onto why it does have some effect and how you should use it.
Copper’s immpasibility is poor when compared to other barrier options
Above is an overview of our experiment testing whether copper (in the form of tape, mesh, and pipe) could prevent slugs and snails from eating plants. The experiment revealed that copper did not stop them, as slugs and snails were able to cross the barriers, as shown on the right.
However, this doesn’t mean copper has no repellent effect; rather, it demonstrates that slugs and snails are capable of overcoming it. To investigate further, we conducted another experiment to compare its ability to stop slugs against other barriers. This allowed us to rank the barriers from best to worst, and we share that information here:
In our third experiment involving copper as a snail repellent, we aimed to determine whether copper has any deterrent effect on slugs and snails at all. By this point, we had observed that many seemed to cross it with ease.
To test this, we designed an experiment to see whether slugs and snails would prefer to move over copper or a different metal, which served as our control. As shown below, we placed numerous slugs on a slug stand filled with salty water, forcing them to exit only via the pipe pathways. We then counted how many slugs left via the chrome-plated pipe and how many left via the copper pipe.
If copper had no repellent effect, we would expect an equal number of slugs to leave through each pathway—for example, 10 via the chrome pipe and 10 via the copper pipe.
In our experiment, 20 slugs left the slug stand, with many attempting to cross the moat, as shown in the picture below. Ultimately, 19 slugs exited via the chrome pathway, while only 1 opted for the copper pipe exit. These results lead us to conclude that copper does indeed act as a repellent for slugs and snails.
However, this raises the question: should you buy or use it? Our recommendation is that copper shouldn’t be a first choice as a barrier, but can be useful as a supplimentary barrier alongside others and that’s how it should be used.
We evaluate each of the barriers we test on a 30-point scale, with the “impassability” factor receiving a 3x weighting, making up half of the total score since it’s the most crucial aspect.
very poor = 1, poor = 2, fair = 3, good = 4, excellent = 5
Copper Tape
Overall Rating: 16 – Fair
Impassability:
Rating: Poor – 6
Environmental impact:
Rating: fair – 3
Cost-Effectiveness:
Rating: Poor – 2
Maintenance Required:
Rating: Excellent – 5
Summary
Copper has some ability to stop certain slugs and snails, some of the time. However, we don’t believe it should ever be your first line of defense when choosing a slug and snail barrier—though using a barrier is a great idea. That said, copper could potentially enhance other barriers when used in combination. For example, adding copper tape to a slug fence, slug collar, or slug stand could further improve barriers that are already more effective.
It’s worth investing in the best barrier, as they tend to pay for themselves over time. Even the most expensive slug collars, fences, and slug stands can save multiple plants each year, making them a cost-effective solution in the long run.
You can read our complete guide on stopping slugs and snails in your garden by clicking here. The guide outlines three key steps to follow:
- Step 1: Manage the environment
- Step 2: Choose an appropriate slug and snail repellent or barrier
- Step 3: Remove or eliminate slugs and snails from your garden
To watch our copper experiment video, check it out below.