Are Coffee Grounds Good For Tomato Plants? Yes, but…

Last update
are coffee grounds good for tomato plants

Do you like coffee? How about your tomato plants? Let’s answer the question: Are coffee grounds good for tomato plants?

The short answer is YES!

So the next time you finish brewing a pot of coffee, don’t throw away the grounds—put them to good use in your garden!

I’ll cover why coffee grounds are suitable for growing tomatoes and how you can use them. But stay with me till the end because there can be some negative effects too which you need to avoid.

The Benefits Of Coffee Grounds For Tomato Plants

Coffee grounds can be a great natural and cost-effective way to enhance the growth and health of tomato plants. When used as a fertilizer or compost, coffee grounds provide essential nutrients that can promote the overall well-being of tomato plants.

The dark, rich coffee grounds are packed with organic matter and minerals that are beneficial for plants, including high levels of nitrogen, as well as moderate amounts of phosphorus and potassium.

Apart from the vital nutrients, coffee grounds also improve the soil structure, creating a conducive environment for tomato plants to thrive, allowing the roots to spread and grow more easily.

The organic matter in the coffee grounds helps to enhance soil fertility and water retention, preventing the soil from becoming too compact or drying out too quickly.

Additionally, coffee grounds have been found to repel certain pests that are harmful to tomato plants. For example, slugs and snails tend to avoid areas treated with coffee grounds, making them a natural deterrent for these common garden pests.

Using Coffee Grounds As Mulch for Tomato Plants

Mulching around tomato plants with coffee grounds is a cost-effective and sustainable gardening practice that can provide numerous benefits. Coffee grounds, rich in nitrogen and organic matter, can help retain moisture in the soil, suppress weeds, and add nutrients that support the growth and productivity of tomato plants.

To apply coffee grounds as mulch, follow these simple steps:

1. Gather coffee grounds: Collect used coffee grounds from your daily brewing or visit your local coffee shop and ask if they have any to spare. Aim to accumulate enough coffee grounds to create a layer around your tomato plants.

2. Prepare the soil: Before applying coffee grounds, ensure that the soil around your tomato plants is weed-free and well-hydrated. Remove any existing weeds or unwanted plant material, and water the area thoroughly if needed.

3. Apply the coffee grounds: Spread a layer of coffee grounds around each tomato plant, ensuring that the mulch is evenly distributed and doesn’t touch the main stem. Aim for a thickness of around half an inch (1-2 cm). Take care not to overload the plant with coffee grounds, as too much nitrogen can have adverse effects.

4. Water the mulch: After applying the coffee grounds, water the mulched area gently to help settle the grounds and encourage nutrient absorption into the soil. Avoid excessive watering that may lead to water pooling or seedling damage.

5. Monitor and maintain: Regularly inspect your tomato plants and the mulched area to ensure that the coffee grounds are adequately benefiting your plants. Adjust the amount of coffee grounds used if necessary, keeping in mind the specific needs of your tomatoes.

By using coffee grounds as mulch for your tomato plants, you can enjoy the benefits of improved moisture retention, weed suppression, and nutrient enrichment. Over time, as the coffee grounds break down, they will further contribute to the overall health and fertility of your garden soil. Give this sustainable gardening practice a try and witness the positive impact it can have on your tomato plants.

Incorporating Coffee Grounds Into Soil Amendments

By combining coffee grounds with other organic materials, such as compost or leaf mold, you can create nutrient-rich soil amendments that will provide your tomato plants with a steady supply of nutrients throughout the growing season.

One recipe for incorporating coffee grounds into compost or soil amendments involves mixing equal parts coffee grounds, compost, and leaf mold in a large container or compost bin. Coffee grounds provide nitrogen, which is vital for plant growth, while compost and leaf mold add additional organic matter and nutrients.

Mix thoroughly to ensure that the coffee grounds are evenly distributed throughout the mixture. This blend can then be added directly to the soil around your tomato plants or used as a top dressing to provide a slow-release source of nutrients.

Another method for incorporating coffee grounds into soil amendments is to layer them in a compost pile. Start by creating a base layer of organic materials, such as leaves or straw. Then, add a layer of coffee grounds on top of the base layer.

Repeat the process, alternating between layers of organic materials and coffee grounds until the compost pile reaches the desired size. As the pile decomposes, the coffee grounds will break down and release their nutrients into the compost, creating a nutrient-rich soil amendment.

In addition to being a valuable source of nutrients, coffee grounds can also help improve soil structure. The organic matter in the coffee grounds acts as a soil conditioner, helping to loosen compacted soil and improve drainage.

This can be particularly beneficial for tomato plants, as they prefer well-draining soil that is rich in organic matter.

Overall, incorporating coffee grounds into compost or soil amendments is a simple and effective way to enhance the health of your tomato plants.

Using Coffee Grounds In Homemade Fertilizers For Tomato Plants

One simple recipe for a DIY fertilizer using coffee grounds is to mix them with other organic materials such as compost or aged manure.

  1. Start by collecting a sufficient quantity of coffee grounds, ensuring they are fully dried.
  2. Combine them with equal parts compost or aged manure and thoroughly mix the ingredients together. This mixture can then be applied directly to the soil around the base of tomato plants, being careful not to cover the stem.
  3. Gently incorporate the fertilizer into the top layer of soil and water as usual.

Another method for utilizing coffee grounds as a homemade fertilizer involves creating a liquid concentrate.

  1. To do this, add about two cups of dried coffee grounds to a five-gallon (20 l) bucket of water.
  2. Let the mixture steep for several days, stirring occasionally.
  3. Once the water has absorbed the beneficial properties of the coffee grounds, strain the liquid to remove any solids, resulting in a nutrient-rich concentrate.
  4. Dilute the concentrate by mixing one part of the liquid with two parts of water and use it to water the tomato plants regularly.

Note: it is important to note that excessive use of coffee grounds can lead to over-fertilization, which may negatively impact the health of tomato plants. Therefore, moderation is key when incorporating coffee grounds into homemade fertilizers.

Precautions And Tips For Using Coffee Grounds on Tomato Plants

It is crucial to be mindful of potential negative effects that may arise from using too much coffee grounds on tomato plants.

But first, let’s see what about pH? Many say that coffee grounds are acidic and need to be applied carefully.

Well, it’s a myth:

Contrary to popular belief, it’s a myth that coffee grounds are acidic and will lower the pH of the soil. After brewing, the grounds are close to pH neutral, between 6.5 and 6.8. Research shows that whatever change coffee grounds bring to the soil is short-lived

Linda Brewer, Oregon State University Extension Service soil scientist

Moreover, excessive use of coffee grounds may attract pests, particularly slugs and snails. These critters are drawn to the organic matter and moisture present in coffee grounds.

To mitigate this risk, it is recommended to create a barrier around the tomato plants with materials like crushed eggshells, diatomaceous earth, or copper tape. These barriers act as deterrents, preventing pests from reaching the plants.

To maximize the benefits of using coffee grounds on tomato plants, it is essential to follow certain precautions and tips:

Firstly, it is crucial to allow coffee grounds to decompose before applying them to the soil. Decomposition helps break down organic matter and release nutrients gradually. Therefore, composting coffee grounds or allowing them to age for a few weeks prior to use is beneficial.

It is recommended to mix coffee grounds with other compost or organic material, such as leaves or grass clippings, to create a well-balanced and nutrient-rich soil amendment for tomato plants.

Another important consideration is the quality and source of coffee grounds. Organic coffee grounds obtained from reputable sources are preferred, as they are less likely to contain harmful chemicals or pesticides.

Similarly, ensuring that the coffee grounds are free from mold or fungus is essential, as these can harm the tomato plants.

Lastly, it is advisable to mix coffee grounds with other organic matter, such as compost or well-rotted manure, before adding it to the soil. This helps create a more balanced nutrient composition and prevents any potential nutrient imbalances.

It is also crucial to water the tomato plants regularly to prevent the coffee grounds from becoming too dry or compacted.


Using coffee grounds for growing tomato plants has several benefits and there are various methods to incorporate these grounds into your gardening routine.

Coffee grounds act as a natural fertilizer, providing essential nutrients such as nitrogen, phosphorus, and potassium to the soil. Additionally, they improve the drainage and water retention capabilities of the soil, leading to healthier and more robust tomato plants.

Incorporating coffee grounds into your gardening routine is a simple and cost-effective way to promote the health and productivity of tomato plants.

By utilizing coffee grounds as a natural fertilizer and pest deterrent, you can enhance the overall growth and yield of your tomato plants.

FAQ about using coffee grounds for growing tomatoes

Do I need to compost coffee grounds before using them?

Coffee grounds are a popular ingredient for composting due to their high nitrogen content. However, there is some debate about whether or not it is necessary to compost coffee grounds before using them in your garden. Some gardeners argue that coffee grounds should be composted prior to use to allow them to break down further and prevent them from clumping together. This is especially important if you plan to apply the coffee grounds directly to your plants, as clumps of undecomposed coffee grounds can create an anaerobic environment that may harm your plants’ roots.

On the other hand, many gardeners believe that composting coffee grounds is not necessary. They argue that coffee grounds are relatively small and break down quickly, so they can be safely added to your garden without going through the composting process. Additionally, coffee grounds are known to attract earthworms, which are beneficial for your soil as they help to aerate it and break down organic matter.

Ultimately, the decision of whether or not to compost coffee grounds before using them is up to you. If you have the time and resources, composting them can help ensure that they are fully decomposed and easier to work with. However, if you are short on time or simply prefer to skip the composting step, adding coffee grounds directly to your garden can still provide many benefits for your plants. Just be sure to spread them out evenly and avoid large clumps to prevent any potential issues.

Can I apply coffee grounds directly to tomato plants?

Yes, but with some precautions. It is advised to mix coffee grounds with other organic matter, such as compost or soil, to avoid creating a concentrated layer that could potentially harm the plants. A good ratio is to use one part coffee grounds to three parts organic matter. This mixture can then be applied around the base of the tomato plants, ensuring it does not touch the stems directly.

How often should I use coffee grounds on my tomato plants?

Both fresh and used coffee grounds can be used for tomato plants. While fresh coffee grounds may have a higher nutrient content, used coffee grounds still contain valuable amounts of nitrogen and other essential elements. If you choose to use used grounds, it is advisable to either compost them or let them dry before applying them to the soil. This will help prevent any potential issues with molds or pests.

Photo of author


I'm a keen hobby gardener. I love growing fruits and vegetables, especially tomatoes. I'm also a certified instructor of the Square Foot Gardening Foundation.