Using Coffee Grounds as Fertilizer


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coffee grounds for plants

If you’re a coffee-loving gardener, you probably know about the hype surrounding coffee grounds and their potential uses on plants. Whether you brew your own cup every morning or your local coffee shop gives out used grounds for free, you could be wondering if this organic material is healthy for your plants.

Can you use coffee grounds as fertilizer? Are they harmful to some plants, and which plants are they good for? Let’s see how you can put your used coffee grounds to work!

Plants and Coffee Grounds

For optimal plant growth, we need to add essential nutrients to the soil. Over time, the growth of your plants depletes the natural nutrients found in the soil. That’s why it’s recommended to fertilize the soil frequently. Moreover, if you buy commercial fertilizers, they will provide your soil with macro-nutrients, such as potassium, phosphorus, and nitrogen.

However, coffee grounds, or the ground coffee beans that are left behind in a coffee pot, contain a lot of those nutrients. Plus, they are full of magnesium, iron, chromium, and calcium. Introducing them to your soil can improve the health of your garden or container plants. Additionally, it’s a useful option for recycling coffee grounds.

Benefits of Coffee Grounds

Fresh or used coffee grounds are an organic substance. They can fertilize plants, improve the quality of soil, and help you deter pests. Still, to reap their full benefits, you should know when to use them and when to avoid them. Here’s what coffee grounds can do for your plants:

  • Improve soil aeration and drainage
  • Help with water retention
  • Boost nitrogen content
  • Act as a pest and cat repellent
  • Promote worm growth in your garden
  • Reduce chemical use and waste

While using coffee grounds as fertilizer can produce lush leafy growth, research shows that they can harm your plants if used incorrectly. For example, they can create a solid barrier over your soil. What’s more, they can dry out your plants.

Also, caffeine could hinder seedling growth. If you use fresh coffee grounds, you can increase the acid content and lower the pH in the soil. In theory, this is beneficial to acid-loving plants, such as azaleas or blueberries. Yet, the acid in the grounds is soluble and will break down once you water your plants. So how can you reap the benefits of coffee grounds for your plants while avoiding some of the drawbacks?

How You Can Use Coffee Grounds for Plants

Any lover of filtered coffee will ultimately throw away a lot of used grounds on a daily basis. If you want to reuse your morning coffee grounds on your plants, you can do so in several ways.

1. Compost

You can compost old grounds and paper coffee filters. This is as simple as adding the coffee grounds and filters to your compost bin. The grounds are helpful because they will increase the nitrogen content in the compost pile.

Furthermore, coffee grounds are a green compost material. Hence, you will need to add other brown compost materials to balance your pile. Generally, the safest way to do this is to have a four-to-one ratio of brown and green compost material.

2. Fertilizer

The most common method is to simply add the coffee grounds on top of the soil. Then, they will act as a slow-release fertilizer. This will boost organic matter in the soil. As mentioned, coffee grounds contain macro and micronutrients that improve soil structure. What’s more, used coffee grounds have a neutral pH, meaning that you shouldn’t be concerned about acidity.

To use your coffee grounds, simply sprinkle them on top of the soil. Then, they will increase the nitrogen content. However, you should avoid piling up the grounds. If you have too many coffee grounds on your soil, you’ll create a water-resistant barrier. Another tip is to mix them with water. You could put two cups of coffee grounds into a bucket with five gallons of water. Then, you’ll end up with an effective liquid fertilizer for container and garden plants.

Another way to use coffee grounds for plants is to invest in a composting vertical garden planter. You can use coffee grounds with Garden Tower 2, a garden planter that accommodates up to 50 plants. This container garden allows you to load compostable materials such as coffee grounds into a vermicompost tube or a two-gallon drawer. Alternatively, you can put coffee beans directly onto the soil in the opening pockets of Garden Tower 2 to give your plants a healthier diet without harmful chemicals.

Also Read: How often should you fertilize your garden?

3. Mulch

While mulch can be useful for your garden, it is also expensive and hard to come by. Coffee grounds are an alternative, but they can inhibit growth if you use them to make a thick layer. Instead, you should mix them with other organic substances. That includes compost or dry leaves. That way, the mulch will contain different particle sizes. It will promote a healthy garden soil structure.
Plants That Love Coffee Grounds
For maximum success, you could focus on specific plants that will benefit from coffee grounds. These are moisture-loving plants such as:

  • Marigold
  • Crinum
  • Calla
  • Hibiscus
  • Meadowsweet
  • Lily of the valley
  • Iris
  • Elephant ear
  • Bugbane

Of course, there are other plants that love moisture. The best tip here is to experiment on your own and use coffee grounds on moisture-friendly plants. However, there are several plants that will not benefit from coffee grounds. They are:

  • Lavender
  • Rosemary
  • Pothos
  • Orchids
  • Spider plant
  • Black-eyed Susan
  • Snake plant
  • Yucca
  • Tomatoes
  • Cactus and succulents


Overall, plant experts and studies have proven that coffee grounds have amazing benefits for plants, but only if they are used correctly. The general advice of botanists is to use coffee grounds in moderation.

Simply add them to your compost pile, mix them into the soil, or dilute them with water beforehand. Stick to using coffee grounds on the plants that we’ve listed or even consider investing in the Garden Tower 2 composting vertical garden planter to maximize the healthy growth and lush look of your plants. Then, observe the results and see what happens. If it all works out, you may just learn that you’re not the only coffee aficionado in your home! Good luck!

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