Do Gardenia Plants Like Coffee Grounds? (Tips for Fertilizing Gardenias)

Gardenias are notorious for their sensitivity and can be a difficult plant to grow when their soil conditions are not right. This includes providing the right fertilizers, like coffee grounds. We’re going to examine the question do gardenia plants like coffee grounds?

Coffee grounds play an important role in providing nutrients for plants. It gives the soil an important boost in nitrogen, which is an essential mineral that plants need to optimize energy use when growing. Coffee also delivers other side benefits, which we will discuss in detail below.

Do Gardenia Plants Like Coffee Grounds

However, before we begin to explore the relationship between gardenias and coffee grounds, let’s establish what soil conditions gardenias thrive in.

What Soil Conditions do Gardenias Like?

Gardenias require a humus-rich soil that is slightly acidic and well drained. This means you should regularly mix in organic matter, like compost, to the soil around your gardenia bushes.

Gardenias like soil that has good drainage, but stays moist. It helps to add mulch around your gardenia plants to prevent evaporation and reduce weeds that will compete for nutrients.

Do Gardenia Plants Like Coffee Grounds?

Gardenia White Flower

As we have established above, gardenia plants will benefit from the addition of coffee grounds to their soil. The coffee grounds help to maintain the conditions where gardenias flourish. Not only do they help to make the soil humus-rich, they are high in both nitrogen and potassium. Both of these nutrients are essential for plant growth and help to establish a good rooting structure.

Let’s take a closer look at the other benefits of coffee grounds for your gardenias.

Coffee grounds benefits for Gardenias

  • Maintain Acidity – if you were to measure the pH level of fresh coffee grounds, they generally measure around 6.0-6.2, which is slightly acidic. This is perfect for plants, like gardenias, that like an acidic soil.
  • Boost in Nitrogen – a study conducted by Oregon State University found that coffee grounds are approximately 2% nitrogen by volume. Nitrogen is considered one of the more important components for plant growth. It is actually part of the chlorophyll molecule (the green part of the plant), which is part of the process for producing food for the plant via photosynthesis.
  • Keeps Pests Away – fresh coffee grounds are well-known for their repelling properties against common garden pests like slugs and snails.

What Kind of Coffee Grounds to Use for Gardenias?

Photographer: Tyler Nix | Credit: Unsplash

When using coffee grounds in your garden, we recommend only using freshly used coffee grounds. It is best to use coffee grounds that have only been brewed in the past 24 hours.

Coffee grounds more than a day old, risks the development of mold or bacteria growth. Which means you may introduce harmful diseases and organisms that will either harm or compete for nutrients with your gardenia.

Where to Source Coffee Grounds?

If you don’t personally brew your own coffee, you can try sourcing leftover coffee grounds from your local coffee shops.

You could simply walk in on the day and ask. However, it is likely you will catch the owner off-guard and unprepared – especially if they are busy. Take it from us as previous café owners, they will always appreciate advance notice. This allows them to make preparations, and it won’t interrupt their busy processes when customers are about. It also doesn’t hurt if you buy a cup of coffee or two to support your local café!

Local Coffee Shops are great places to source used coffee grounds

How do you fertilize Gardenias with Coffee? Gardenia Fertilizing Tips

Okay, so we know that coffee grounds are good for the soil around gardenia plants. But how exactly do you use coffee grounds as fertilizer? Here are a few methods for applying ground coffee to your gardenias.

Sprinkling coffee grounds on top of the soil

The fastest and easiest method of applying coffee grounds to your soil is by sprinkling the raw used coffee grounds directly to the topsoil. When we are short for time, we use this method.

The coffee grounds will act a bit like an organic mulch and help to keep weeds away.

Sometimes we like to fold the coffee grounds into the top few inches of the soil. This not only helps to increase the soils’ organic matter content, it helps for air circulation in the soil – something that doesn’t happen enough for outdoor plants.

Create a Liquid Fertilizer from Coffee Grounds

Another method of delivering the nutritional benefits of coffee grounds to gardenias is making your own DIY coffee liquid fertilizer. Simply mix in your coffee grounds with water and give it a good stir. Allow the mixture to steep for a minimum of 12 hours before applying to your garden.


To give your fertilizer a boost, add some worm castings into your mixture to supercharge it.

Add Your Coffee Grounds to Your Compost

By adding raw used coffee grounds to your compost, you can give it a boost in nitrogen and potassium. So, when you go to mix in your homemade fertilizer compost into your garden, you’ll be spreading the love around.

The heat in the compost prevents any bacteria or mold from growing on the coffee grounds, keeping them sterile and untainted for your gardenias.

adding coffee grounds to compost

How Often Should I put Coffee Grounds on my Gardenia?

Depending on the method you choose to apply the coffee grounds to your gardenias, we would suggest fortnightly applications of coffee ground fertilizer for your plants.

During the gardenia’s growing seasons (mainly spring and summer months), you can increase the applications to weekly, to ensure your outdoor gardenias have that nitrogen boost for optimal growth.

Final Thoughts for do gardenia plants like coffee grounds

Coffee grounds are the perfect complementary fertilizer for your gardenias. It provides the much-needed nitrogen sources for healthy growth, as well as helps to maintain a slightly acidic environment in the soil.

There are many methods to apply coffee grounds to your gardenia plants. Our favorite way is creating a coffee ground liquid fertilizer combined with worm castings, for a super-charged fertilizer that your gardenias will love.