How To Make Caffeine Spray For Slugs ( Fast & Easy )

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There are a lot of home remedies for getting rid of slugs, I have personally tested a lot of these out, some of them do not work at all while others do make wonders. Before you think of what you want to use against slugs you have to decide if you want to kill the slugs or repel them. Both of them have their pros and cons, but the good news is that a well-made caffeine spray for slugs will definitely kill them.

You can make caffeine spray for slugs by brewing 2-3 regular cups of coffee each in 1 oz of water. Do not dilute the caffeine spray with water, your main goal is to get a high concentration of caffeine in the spray which actually kills the slugs. You will need a concentration of around 1-3% of caffeine in the solution to maximize the effectiveness of the slug spray.

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If you have ever tried using coffee grounds to deter slugs then you have most likely noticed that the slugs simply do not care. Although caffeine is toxic to the slugs they do not actually eat the coffee grounds or absorb any of it. Instead of placing coffee grounds around your plants, you should make a caffeine spray for slugs. According to caffeine does kill slugs, but it all depends on how you use it.

If you sprinkle coffee grounds around your plants then you are just wasting your time, even if the slugs would eat it the caffeine concentration is way too low to actually harm them. If you have been using grass clippings as mulch then you might have noticed more slugs, for more information check out my recent article Grass Clippings As Mulch Pros And Cons ( Top 16 Pros and Cons ).

How To Make Caffeine Spray For Slugs

In my personal experience, making a caffeine spray for slugs can be an effective and natural way to deter these pesky garden pests. To create the spray, I start by brewing a strong cup of coffee using used coffee grounds. Once the coffee has cooled, I strain out the grounds and transfer the liquid to a spray bottle. To enhance the effectiveness, I sometimes add a small amount of dish soap to help the caffeine stick to the slugs’ bodies.

When I spot slug activity in my garden, I spray the solution directly on the slugs and around the areas they frequent. The caffeine acts as a repellent, disrupting their feeding and movement patterns. It’s important to reapply the spray after rainfall or heavy watering.

Make An Effective Caffeine Spray For Slugs

In order for your caffeine spray to work against slugs, you will need to make it as concentrated as possible. A lot of people will tell you to just brew a cup of coffee and dilute it with water, but the truth is that this doesn’t work. The higher the concentration of caffeine in the spray the more effective it will be, my suggestion is to use regular coffee instead of instant coffee as regular coffee tends to have a higher concentration of caffeine.

Brew 2-3 cups of coffee, and use around 1 oz of water per cup, and do not dilute it further with water. Let it cool off in a container, after it has cooled add it to the spray bottle, make sure before using it to give it a good shake. After you have sprayed the caffeine spray around your plants the slugs will be munching on your mulch or even plants. As they are eating they will inevitably ingest the highly concentrated caffeine which poisons them. If you also have a tick problem then check out my recent article How to get rid of ticks in the house naturally? ( Top 16 Ways ).

Do Not Spray The Caffeine Spray For Slugs Directly On Your Plants

While you are using the caffeine spray make sure to spray the area around your plants, and not the actual plants. Most plants will not suffer from some caffeine, but as the spray is highly concentrated some will be harmed if you spray it directly onto them. The problem with the highly concentrated caffeine spray is that the caffeine actually increases the acidity of the soil and especially if you spray it directly on the plants.

Some plants like blueberries need highly acidic soil, so you might notice that they will grow even better. On the other hand, you should stick to spraying only the soil around the plants as this is still the most effective way of killing the slugs. If you are planning on using grass clippings around your trees then check out my recent article Grass Clippings Around Trees ( Top 5 Do’s ).

Use The Caffeine Spray For Slugs After The Rain

The most common mistake which people make while using a caffeine spray against slugs is that they will use the spray during a sunny day. As you have probably noticed most slugs will come out in large numbers after a rain, and rain tends to wash away everything, including the caffeine spray. Once the rain has stopped, go out and use the caffeine spray, and you will notice significantly better results this way.

Use The Caffeine Spray For Slugs In The Evening

If your area doesn’t get that frequent rains you will still see plenty of slugs coming out of their hideouts during the cooler nights. This is an excellent time for them to eat the sprayed mulch, so make sure to spray during the evening. Make sure to spray around your plants and in areas where you might think the slugs are hiding, below planks of wood, empty containers, and so on, this way you will get them before they can do any damage.

How Often To Use The Caffeine Spray For Slugs

Ideally, you should use the caffeine spray once a week, but this mostly depends on how effective the spray actually is at killing the slugs. If you live in an area where slugs are living in large numbers then you might have to use the spray more than once a week. If you see good results after the first spraying then continue spraying the ground for a couple of days until you notice that the number of slugs has decreased, from then on it should be enough once a week.

Key Takeaways

  • Start by brewing a pot of strong coffee using regular coffee grounds. The caffeine in the coffee acts as a natural deterrent for slugs and can help control their population in your garden.
  • Once the coffee has cooled down, dilute it with water in a ratio of 1 part coffee to 3 parts water. This will create a caffeine spray that is safe to use on your plants.
  • Transfer the diluted coffee into a spray bottle and apply it directly to the affected areas where slugs are present or likely to appear. Spray the solution on the leaves, stems, and soil around your plants. The caffeine in the spray will deter the slugs, as they are sensitive to its effects, helping to protect your plants from their feeding damage.