Do Roses Like Coffee Grounds? Are They Good To Use?

Do Roses Like Coffee Grounds? Are They Good To Use?

If you’re a coffee drinker and like to grind your own fresh beans to use either in your espresso machine or drip coffee maker, you’re going to end up with lots of used coffee grounds. As you look for ways to repurpose those grounds, you might ask: “Do roses like coffee grounds?”

Even those of you who purchase already ground coffee will still end up with a lot of used grounds at the end of the week. And, as these are organic and high in nitrogen, we don’t want to waste them, do we?

Most of the time, my used coffee grounds end up in the compost pile or compost bin because I know that they’ll add plenty of nutrients to the other composting materials. This, in turn, provides my garden with lovely fresh compost to feed all the plants that I grow.

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However, from time to time, I do like to use the coffee grounds around the garden to help certain plants that can benefit from them. For example, coffee grounds are quite acidic and a handful scattered around my hydrangeas can achieve some amazing color transformations in the flowers.

But, before you start lavishing your roses with all of those used coffee grounds that you collect each week, let’s have a look at what they can offer your precious blooms.

The Lowdown On Coffee Grounds

Before we can determine whether coffee grounds are good for roses, we need to understand their composition and what effect they can have on certain plants.

Scientifically speaking, the chemical composition of used coffee grounds consists of sugars, proteins and lignins. 

According to an analysis done by the North Carolina State University, the major nutrient ratio of coffee grounds is 2.1:0.3:0.3.

Or, put more simply, coffee grounds contain:

  • 2.1 parts nitrogen
  • 0.3 parts phosphorus
  • 0.3 parts potassium

This is commonly referred to as the N:P:K ratio and determines how much of each nutrient is present in any fertilizer that you might be using in your garden.

When I look at that ratio, I can see immediately that coffee grounds contain a very high amount of nitrogen. Of course, this is an essential nutrient for all plant growth.

On the other hand, used coffee grounds contain a much smaller portion of potassium. And, this is the essential nutrient for flowering and fruiting.

So, based on this alone, I would assume that giving your roses used coffee grounds would certainly result in a lot of foliage growth but not enough blooms. 

That is unless you like to enjoy some banana cake with your coffee too! More on that later.

But, apart from their nutritional content, used coffee grounds also have other benefits for plants and a healthy soil environment.

The Benefits Of Coffee Grounds When Added To The Soil

Apart from adding important nutrients like nitrogen to the soil, used coffee grounds do have other benefits. For example, they help to attract and feed earthworms which is a good thing.

Now, if you’ve been gardening for a while, you’ll know how beneficial earthworms are to your soil health and the soil structure overall. I know I always get excited to find some lovely fat worms in the soil when I’m digging a hole for a new plant.

That’s because earthworms improve the structure of the soil by tunnelling through it and creating air and water pockets for healthy root growth. This also helps to improve soil drainage. 

On top of that, earthworms produce excrement called castings which are high in beneficial nutrients.

The other benefit that coffee grounds add to the soil is that they generally lower the pH level. So, if you have overly alkaline soil, used coffee grounds can be a huge benefit.

You see, used coffee grounds are acidic which is why they can easily lower the soil pH. This makes them ideal for use around acid-loving plants such as tomatoes and citrus trees.

Essential Nutrients That Your Rose Garden Needs For Optimum Growth

So, now that we know all the benefits that coffee grounds add to the soil, let’s learn about the vital nutrients that roses need for optimum growth.

Firstly, roses, like all plants, need nitrogen. Nitrogen is responsible for green plant growth. In this case, used coffee grounds do tick all the right boxes.

However, rose plants also need a decent amount of phosphorus for great root development. Remember that it’s the roots that feed the plant with the nutrients that are found in the soil. 

The roots are also responsible for the transportation of water from the soil into the plant itself. Plus, they support your rose bushes as they continue to grow and thrive.

One of the most important nutrients necessary for lots of colorful blooms though, is potassium. Without sufficient of this vital nutrient, you might end up with lots of lovely green foliage but very few blooms.

And, it’s those gorgeous flowers that we rose growers covet the most, right?

So, although used coffee grounds will add some benefit to the growth of our roses, they do fall short when it comes to producing plenty of lovely blooms.

But, I do have a solution for that problem that I’ll share with you shortly. First, let’s look at the soil requirements for growing healthy and lush rose bushes.

The Best Soil Quality For Healthy Roses

To be perfectly honest here, I’ve grown roses quite successfully in a wide range of soils from heavy clay to sandy loam. That’s because I could supplement the plants with the necessary nutrients to help them thrive.

But, if you’re starting from scratch, nice loamy soil with plenty of organic material will get your rose bushes off to a good start. If your soil also has a decent clay subsoil, your roses will love that too.

The most important thing to remember is that the soil should be free-draining and contain lots of organic matter. So, if you make your own compost (including those used coffee grounds), add this to the soil before planting your roses.

The soil pH should be somewhere within the region of 6.5 and 7. This is considered slightly acidic to neutral. Before planting your roses, you should do a pH test of the soil. This will give you an idea of whether you need to amend the soil or not.

If your soil is alkaline (the pH is much higher than 7) then used coffee grounds can be a useful addition to lower the pH level. However, if your soil is already acidic, refrain from adding coffee grounds and add some agricultural lime instead.

Should You Use Coffee Grounds Around Your Roses?

The use of coffee grounds can be beneficial to your roses as long as you don’t overdo it or apply them at the wrong time. Adding too much coffee grounds could damage the roots of your plants. 

Applying a small dose of coffee grounds to the soil around your roses in early spring can be very beneficial. The added nitrogen will help to stimulate lots of new growth as your rose bushes come out of their winter dormancy.

Plus, this addition of nitrogen will also help to make your roses stronger and more disease-resistant. But, always remember to use moderation as too much nitrogen can damage the root system of your plants.

However, avoid giving your roses used coffee grounds in the fall or autumn as this could stimulate tender young growth that will be damaged once the cold weather arrives. It’s also important not to feed anything to your roses in winter as they’ll be dormant.

How To Safely Apply Coffee Grounds To Your Roses

Here are a few suggestions on how you can safely apply coffee grounds to your roses.

Sprinkle And Water In Early Spring

For this method, you want around 2 cups of used coffee grounds for each rose plant and a watering can full of water.

Just sprinkle the used coffee grounds on top of the soil all around each plant. Take care not to get the grounds onto the stems of your rose bushes. 

Then, just water the soil really well using a hose or a watering can full of water. You want to ensure that the water pushes the coffee grounds down into the soil. 

This will make the nitrogen available for the roots of your roses to take up.

Make A Liquid Fertilizer

Use two cups or half a pound of coffee grounds and add this into a watering can filled with water. Use 2 gallons of water (9 litres) in a large watering can for this. Stir the mixture really well so that the coffee grounds are dissolved as much as possible. 

Water this mixture around the base of each rose plant so that it seeps into the soil. Once again, you only want to apply this in early spring to give your roses a good boost of growth.

​Put Your Coffee Grounds Into The Compost

You can also do what I do most of the time and add the coffee grounds to your compost. They break down fairly quickly and you can then spread the compost around your rose bushes. 

Not only does this feed your plants but it can also inhibit weed growth. Once again, the best time to do this is in spring as your plants come out of dormancy.

Make A Nutrient Rich Brew For A Full Dose Of Nutrients

Here is my personal tip for giving your roses all the nutrients that they’re going to need to produce healthy new growth as well as tons of blooms.

Remember when I mentioned whether you like banana cake with your coffee? Well, I forgot to say that it should be homemade banana cake so that you end up with lots of banana skins.

You see, bananas are high in potassium and rose bushes absolutely love banana peels. In fact, every time I plant a new rose bush, I always put a piece of banana skin in the bottom of the planting hole.

As the skin breaks down, it releases lots of nutritious potassium to encourage my rose bushes to produce the most magnificent blooms. This is a great way to get your plants off to a good start.

You can use this expert tip to make your own highly nutritious brew for your rose bushes.

What you’ll need is some banana skins that you’ve chopped into small pieces. Place these in a large jar filled with water. Put the jar in a cool spot and leave it for around a week or two. 

During this time, the potassium contained in the banana skin will have leached into the water.

After the time is up, drain the nutrient-rich water and pop this into your watering can. You can throw the skins into the compost heap. Now, add 2 cups of coffee grounds to the watering can and fill it with water.

Give the mixture a good stir and then apply it to the soil around your rose bushes. Before long, your rose will not only start producing lots of new growth but there will be flower buds forming as well.

If you want to know more about the benefits of using banana peels in the garden, you can read an article I wrote all about this here.

Where To Source Fresh Coffee Grounds If You’re Not A Coffee Drinker

If you don’t drink coffee yourself or only indulge in it rarely, the best way to get used coffee grinds is by visiting your local cafe or coffee house.

Most of these establishments will be happy to save the grounds for you and will most likely give them to you for free. After all, it means that they don’t have to throw them away and it keeps them out of landfill.

Frequently Asked Questions

What do coffee grounds do to roses?

When applied at the right time and in small doses, coffee grounds can provide an excellent source of nitrogen to your roses. Leftover coffee grounds can also lower the pH of the soil if your soil is too alkaline.

How often should you put coffee grounds on roses?

It’s a good idea to only add coffee grounds around your roses once a year in spring. Make sure you water well using at least a gallon of water for each plant. 

Final Thoughts

​If you’re a coffee drinker, you’ll be pleased to know that coffee grounds are an excellent addition to your garden and your compost pile. However, use them sparingly around roses and only apply them in early spring to promote healthy growth at the beginning of the growing season. 

Remember to only use a small amount because too much nitrogen all at once can burn the roots of your precious rose plants.

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