6 Reasons That Coffee Grounds Are A Miracle For Your Garden

When I was young, I often saw my mum throwing out random brew leftovers in the pots and the garden. I always wondered why — it looked so awful! I asked her and she replied that it was for “nutrition purposes”. “Nutrition or no nutrition, I don’t like it” — I said to myself and forgot all about it.

Several years passed by and I moved away in my first flat. The need of making this place feel like a home arise. I got my first flower pots and my first gardening problems. The leaves of my hibiscus started to turn yellow and fall off for no obvious reason.

I, of course, asked my mum and I guess you can already imagine what she said to me. Yes, coffee grounds. I happen to have a huge coffee addiction so I have a never-ending supply of coffee grounds. But I still thought that coffee leftovers aren’t the prettiest thing. Later I found a solution which I’ll share with you.

I did try coffee grounds as a fertilizer and they’ve done miracles! I still use them from time to time. I remember how hard and time-consuming it was for me to find a solution to my problem. I was thrilled with the results of using coffee grounds and researched some more about their abilities. I found various ways to use coffee waste not only in pots, but in regular gardening too.

Important facts about coffee grounds

  • they are slightly acidic which makes them a good match with most of the plants
  • they slowly release nitrogen into the soil as they degrade
  • a great source of potassium, magnesium and phosphorus
  • a natural slug and snail prevention
  • worms are addicted to coffee… like me!
  • used coffee grounds and eggshells prevent blossom rot on tomatoes
  • cats will avoid coffee grounds from miles

Coffee Grounds and Pots

Hibiscus in a pot and coffee grounds

You should be careful, when you put coffee in pots. Two reasons — coffee tends to dry out in crust, thus making watering difficult. It can also grow a mould of some sort, which you better avoid just in case. You can skip it if you’re worried, but I’m sure that if you’re careful enough you can make it work. I first tried coffee grounds on my hibiscus. My goal was to avoid crust and mould, so I added one cup of grounds to five cups of water. I let the mixture stay like that for a day and then watered the plant with it. The grounds were on the bottom so no crust managed to form. This saved my hibiscus. I use the mixture regularly since.

Alkaline balance

Coffee grounds have a slight acidic power so they will definitely go with acid-loving plants. For example, plants that need pH of 3.0 to 5.5 will thrive. My hibiscus is the living proof. If you are afraid to use coffee on your plants, I suggest to add some lemon/lime juice to it to create more balance in the fertilizer. Lemon will neutralize the acidic power of the coffee, but the nutrients will remain. I advise you to check the pH balance of the soil from time to time just in case. Here’s a small list of acid-loving plants:

  • Gardenia
  • Azalea
  • Juniper
  • Oak
  • Pine
  • Strawberries
  • Ferns
  • Rhododendron
  • Camellia

Recycle used coffee — make your own compost

used coffee grounds in compost

If you throw your grounds in the compost pile it will turn neutral and perfect for all plants. As they decompose they release valuable nitrogen in the soil and prevent bad bacteria. Coffee grounds act as a green material to your compost. What is green material? I’ll explain. Basically there should be two types of materials in your compost. “Brown materials” such as wood chips and dried leaves are carbon-rich, and “green materials” like various kitchen leftovers, add balance. Green materials are rich in nitrogen. A good compost is 95% brown and only 5% green materials.

Worms are addicted to caffeine

Worms make so-called worm compost or vermicompost. As disgusting as it sounds this is a great way to make a nutrient-rich compost. I know why I’m drinking coffee, but why those valuable creatures are addicted to it too? I found out that coffee grounds allow bacteria to grow, which is exactly what worms love to eat. You have to combine coffee grounds with other materials such as raw fruit and vegetable scraps. Avoid processed food, meat and citrus fruits. A great tip I received from some professionals is to leave the coffee to pre-rot. The worms will love you for that even more. Don’t spoil them too much, though. Extra coffee can make the bin acidic.

Coffee grounds can be used to deter pests and cats

One angry looking cat

Let me tell you something. Coffee leftovers are a nuclear option for slugs and snails. That’s right, it may not look pretty, but at least your plants will be safe. That’s not the end of the story.

If you have carrots, you’ll probably have carrot flies. Surprise, surprise — used coffee has a scent that is a natural repellent to those small intruders.

Deter pests & cats with coffee waste

And if you have a cat you probably know that they love your garden as much as you do, for their own reasons. Have no fear — coffee is here. Mix some of the grounds with citrus peelings and watch the magic happen.

Oh, and if you want to make coffee usage not so bad-looking here is my advice. I tend to decorate my pots with river stones. Whenever I want to put some coffee, I take them away. After the soil has soaked, I just put the stones back in the pot — beauty restored.

Overall, coffee grounds can be useful in many ways. And don’t worry if you don’t drink coffee. You can ask any local cafeteria for used coffee grounds.