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Are Coffee Grounds Good for Tomato Plants? Benefits & Tips

tomato plant

If you have a garden or just have a few indoor plants that you take care of, you have probably heard repeatedly that many gardeners use coffee grounds as fertilizer for their plants. This has a double purpose. Not only do you get a great cup of coffee, but the used coffee grounds keep you from having to purchase fertilizer for your plants and garden.

While we’ve shown that coffee grounds are good for some plants, are they actually good for all plants? Are coffee grounds good for tomato plants, for instance? Coffee grounds are good for tomato plants in small quantities. However, using them in large amounts can have a harmful impact.

In this article, we’ll answer all your questions about coffee grounds and tomato plants.

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Are Coffee Grounds Good for Tomato Plants?

In answer to the question, “Are coffee grounds good for tomato plants,” the answer is yes and no. Just like anything you add to your garden, too much of a good thing can lead to disastrous results.

While using coffee grounds for your tomato plants is okay, don’t go overboard with it, or it’ll have the opposite effect.

used coffee grounds from coffee machine
Image Credit: RasaBasa, Shutterstock

How To Use Coffee Grounds for Your Tomato Plants

The best way to use coffee grounds in your tomato garden is to mix them up as a sort of fertilizer. For example, use 20% coffee grounds and 80% mulch or compost mixture, so the coffee isn’t too acidic.

It’s best to let the mixture compost for a bit before applying it to your tomato plants as well. Don’t pour the composting mixture directly on your tomato plants; instead, pour it into the planting soil, then transplant your tomato plant into the soil.

There are a few different ways you can use coffee grounds for your tomato plants. First, you can use them directly, only if they are used already, and put them in the soil. You can also mix them with mulch or compost, which is best, according to the experts.

What Are the Benefits of Spent Coffee Grounds for Tomato Plants?

There are a few benefits to using coffee grounds on your tomato plants.

Adds Nutrients

Coffee grounds contain nitrogen, as well as a few other nutrients that your tomato plants need to grow healthy and vibrant. Using the coffee grounds in moderation and the way you’re supposed to can help add any lost nutrients the plants aren’t getting.

Keep Pests Away

Whether it’s for the tomato plants or some other area of your garden, coffee grounds are said to keep the pests away, something every gardener deals with on a daily basis.

While it’s not 100% guaranteed, coffee grounds seem to be a barrier between your garden and slugs that want to invade and eat your plants.

tomato plant
Image Credit: __Alicja_, Pixabay

Can You Use Fresh Grounds?

While there are plants out there that benefit from fresh grounds, tomato plants aren’t one of them.

Fresh grounds that haven’t been used yet contain a lot of acid, and tomatoes aren’t acid-loving plants and can be burnt by the fresh grounds. It’s best to stick to used coffee grounds for tomatoes.

How Do Coffee Grounds Help Tomato Plants?

Used coffee grounds have several benefits when added to the soil of tomato plants.

  • Balances pH
  • Stabilizes the soil temperature
  • Natural organic insecticide
  • Weed reduction
  • Growth increase rate
  • Promotes earthworm activity
  • Reduces harmful fungi and bacteria

These are only a few of the ways that coffee grounds are helpful to your tomato plants. However, as previously stated, only use them in moderation.

How Often Should I Use Coffee Grounds?

Fertilize your soil with the used coffee grounds when transplanting your tomato seedlings. Fertilize again when you’re transplanting, and then again every two weeks. It’s also best to put the fertilizer around the plant instead of directly on the tomato plant itself.

If you end up using too much on your tomato plants, you’ll see the symptoms below.

woman holding a box of used coffee ground to use as compost in her garden
Image Credit: DGLimages, Shutterstock

Symptoms of Too Much Fertilizer in Tomato Plants

  • Fewer growing tomatoes
  • Poor color
  • Poor texture
  • Poor flavor
  • Dropping too many blossoms
  • Leaves curling and looking burnt

If you see any of these signs and symptoms with your tomato plants, then it’s time to rethink using coffee grounds as a fertilizer. Sometimes it’s best to go with a traditional fertilizer, but you can ask your local garden center for help if the problem persists.

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Final Thoughts

If you love the fresh tomatoes from your very own, well-tended garden, the way that we do, then these tips will help get them from garden to table in the best shape. Before you know it, you’ll be enjoying fresh, bright red tomatoes at the kitchen table with family and friends all through the summer and winter season. What more could you ask for from your garden than that?

Featured Image Credit: congerdesign, Pixabay


Kate MacDonnell

Kate is a lifelong coffee enthusiast and homebrewer who enjoys writing for coffee websites and sampling every kind of coffee known to man. She’s tried unusual coffees from all over the world and owns an unhealthy amount of coffee gear.

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