Why You Should Be Watering Your Plants with Coffee

Why You Should Be Watering Your Plants with Coffee

Jake Bonneman
4 minute read

Did you know that a lot of plants love coffee just as much as you do?


It’s true—here’s why: 

  1. Coffee is packed with nutrients — Coffee contains a lot of nutrients that help plants thrive, such as: potassium, nitrogen, magnesium, and calcium. In particular, the nitrogen in coffee helps plants grow healthier, stronger stems.
  2. Coffee grounds are a great fertilizer — Mixing grounds into compost gives your plants a healthy boost by adding to the organic matter in the soil.
  3. Slugs hate coffee — Coffee is naturally repellent to a lot of pests and is especially effective in keeping slugs and mosquitos away.
  4. Worms love coffee — However you feel about them, worms are helpful in keeping soil healthy. They love to eat coffee grounds—and a little caffeine actually helps them “work” faster and live longer, happier lives in your garden.


For outdoor plants, you can also just sprinkle grounds on top of the soil around your plants. For indoor plants, you’ll want to use brewed (liquid) coffee, since it contains magnesium and potassium.


Most types of plants will appreciate the nutrients and fertilizer that coffee provides, but there are some plants that benefit from being watered with coffee more than others. It’s best to start slow to make sure you don’t overwhelm your plants.


With that in mind, here’s a short list of do’s and don’t’s:

  • Do dilute your coffee before you use it.  Always err on the side of using more water rather than using more coffee. Starting with just a little coffee added to the water will allow you to gauge how your plants react to suddenly receiving the nutrients in coffee.
  • Don’t overfeed your plants with coffee. Plants won’t do well if they get too much acid. More reason to dilute the coffee with lots of water and slowly increase it after you see how your plants react. (At most, you should use a 1:1 ratio of coffee and water.)
  • Do let the coffee cool completely before you water your plants with it.   Plants don’t like having hot beverages poured on them any more than humans do.
  • Don’t use coffee with anything else in it! Don’t empty out the cup of cafe con leche you forgot about from this morning on top of your azaleas. Trust me—you really don’t want to use coffee with creamer, milk, sugar, or artificial sweeteners in it. Most of the basic coffee additives that are delicious to us can actually hurt your plants, or at least stress them out. You can use leftover coffee as long as it’s black.
  • Don’t water a plant with coffee more often than once a week.   I know—It sounds crazy to us, but plants don’t like to drink coffee more often than about once a week. It is possible to have too much of a good thing (at least if you’re a plant).

Who knew plants were just like us?

Again, if you do decide to try watering your plants with coffee, or sprinkle grounds around your outdoor plants, remember to start in moderation until you’re sure your plants can handle all the nutrients.

Hey—more coffee for you, right?


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