Did you know that coffee and the leftover grounds can be a helpful gardening tool? Those grounds can also provide essential nutrients for plants such as roses. While these are two great reasons to apply used coffee grounds throughout your garden, there’s at least one more reason why you’ll want to save your grounds for your garden – slugs, and snails. Slugs and snails can annihilate your garden in no time since their diet consists of plant leaves. Thankfully, a simple home remedy can protect your garden and fend off pesky snails and slugs. In this post, we’ll talk about how to protect your garden with used coffee grounds and fend off slugs and snails.
Why Do Snails & Slugs Find Coffee Repellant?
Slugs and snails despise caffeine, so adding anything rich in caffeine to your garden will function as a strong deterrent. Caffeine occurs naturally in plants such as coffee, cacao, and tea. This instance of floral evolution likely developed as a defense mechanism to prevent insects and other herbivores from eating the plants. Humans are an anomaly in the animal kingdom since we enjoy caffeine while the rest of the animal world tends to avoid it. This means that your leftover decaf coffee will likely not do the trick. The repelling factor is the caffeine, not the brewed coffee or the beans. That being said, you’ll want to use the strongest coffee that you can get your hands on.
Should You Protect Your Garden with Coffee Grounds or Coffee
So, here’s the big question: should you use your old coffee grounds or leftover coffee to protect your garden from snails and slugs? While coffee grounds will suffice, coffee itself is far more effective. This is likely because it’s easier to enrich the soil with caffeine when it is in liquid form. While caffeinated liquid coffee is the better option, coffee grounds are also effective to a point. The abrasive texture of used coffee grounds discourages snails and slugs from crossing over. All in all, liquid coffee infused with caffeine is a more complete option.
According to the USDA, solutions containing 1-2% caffeine can kill slugs and snails within two days. If that’s too inhumane for your style, you can reduce the solution down to 0.01% and it will still function as a repellant.
If the above concentration percentages mean nothing to you, don’t worry, we’ve got you covered. The caffeine concentration of your average bag of coffee beans is somewhere between 0.8% and 2.8%. Instant coffee yields a caffeine concentration of around 0.05% and your standard drip coffee packs a slightly higher than the average instant coffee option.
How Do You Protect Your Garden of Slugs and Snails with Coffee?
In order to achieve the best possible results, you need to brew a pot of highly caffeinated coffee. You then take your pot of caffeinated perfection and pour it around the plants you want to protect. If the first application doesn’t do the trick, you can apply a second round of caffeine-rich coffee to your garden. In addition to ridding your garden of snails and slugs, coffee is also known to deter cats and other garden pests from wrecking your prized Petunias!
Does Coffee Affect Your Plants?
Coffee is an effective means to deter a variety of pests from devouring your precious garden. However, not all plants like coffee, so you’ll want to steer clear of this method around some types of plants. A few examples of plants that despise coffee include tomatoes, clovers, and alfalfa. On the other hand, acid-loving plants like roses, blueberries, azaleas, carrots, radishes, and hydrangeas will benefit from the addition of coffee to the soil.
If you know for certain that your soil is already acidic, you should consider other snail and slug repellants such as wheat bran, diatomaceous earth, or even seaweed. You can also encourage predators, such as ducks, beetles, frogs, and toads, to step up and defend your garden.
The Bottom Line
You can use either coffee grounds or brewed coffee as a natural slug and/or snail repellent. However, highly caffeinated liquid coffee is by far the better option, but not all plants will benefit from the chemical makeup of coffee.
