Are Coffee Grounds Good for Mint?

Last Updated on November 22, 2022 by Stephanie

As with everyone else, you like saving some money when you can. And if you can reduce the amount of waste is even more better. Perhaps thats the reason youre mulling an idea to use coffee ground to the mint plant. But does mint love coffee grounds?

Yes, you can utilize coffee grounds to compost mulch, feedstock, or fertiliser for mint. It improves the soils quality, and also provides nitrogen and other nutrients that promote the growth of your plants. Additionally, it may alter the pH of soil, prevent diseasesand insects.

Coffee grounds are certainly able to be a blessing for mint. If youre not careful they could hold in excess moisture, which can cause problems to your plants.

Today, Im going teach you how to utilize coffee grounds on your mint, without causing harm to your precious plants.

Are Coffee Grounds Good for Mint?

The reason gardeners utilize coffee grounds for fertilization is because theyre brimming with nutrients. One of the most plentiful nutrients is nitrogen which is about 2 percent per volume in coffee ground. (Source: University of Wyoming)

Nitrogen - Coffee grounds quickly release nitrogen, which mints need for healthy growth. It is the most important nutrient needed to grow new stems and leaves. Remember that nitrogen is a vital element of chlorophyll that assists in the process of photosynthesis and turns the foliage green.

Potassium The nutrient is approximately 0.6 percent of ground coffee per volume. Potassium can help your mint develop healthy roots and withstand various stressors, including low light, submerged or even heat.

Phosphorus - A tiny amount of the nutrient P (approx 0.06 percent per volume) can be found within coffee beans. It is essential for the development of roots and flowering.

The coffee grounds are also stuffed with beneficial micronutrients such as magnesium, copper, boron zinc, calcium and iron. All of them help to promote the continuous, strong development that your plants produce.

How Often Should I Put Coffee Grounds on My Mint?

If you have to include coffee grounds in the mint you have, this must be a once in a while thing. In reality, you must adhere to the normal fertilization schedule for your mint, if youre using it for fertilizer.

This means that you should apply grounds of coffee in the early spring when your plants begin to sprout new growth. Then, through the summer months, you must fertilize your plants with coffee grounds every 4 to 6 weeks.

many mint leaves

How Much Coffee Should You Add to Your Mint?

Coffee grounds should be used only sparingly on your mint. The coffee grounds composition should not exceed 5 percent of the soil volume. If you overdo it this, it could hinder the development that your mint is experiencing.

According to Barnyards and Backyards at the University of Wyoming, you should use no more than 1/2-inch of ground when adding direct to soil.

If you apply excessively thick layers of ground coffee, it will begin to compact and hinder how water is absorbed. It could also result in hindering soil air circulation.

Best Way to Use Coffee Ground on Mint

Composting using coffee Grounds

Compositing is by far the most secure and reliable method to use coffee grounds to make mint. Combine them with filter paper into the compost bin, or stack them into a compost pile for use as green feedstock.

Be sure that coffee grounds make up not more than 20 percent of the compost volume. If you go over that amount it could prevent the compost from heating enough to activate microbes which breakdown organic matter and release nutrients.

Some experts recommend mixing one part coffee grounds with four parts of shredded foliage or sawdust as a result of weight.

If youre concerned over the acidity in coffee dregs or grounds, you can add a bit of lime or wood ash to the compost mix to counteract the acidity.

Coffee Grounds as Organic Fertilizer

Coffee grounds can be applied directly on the soil to act as fertilizer. This can help release nitrogen, as well as magnesium and phosphorus, potassium copper, as well as other minerals. Mints will appreciate these in tiny amounts, but be careful not to overdose.

You can rub the grounds of coffee into the top 2 or 3 inches of soil. You can also spread them over the the top of your soil, and allow them to work their work. It is best to apply them during the peak growth period, which is from early spring to the end of summer.

Mix it with Mulch

If you are using coffee grounds to make the mulch, be sure that you spread an even layer that is not greater than 1/2-inch over the over the top. If you use coffee ground mulch that is thicker than this will cause it to compact and create a barrier that will block the air and water.

Make sure to cover the area with organic matter such as wood chips, compost, shredded leaves or shredded bark. The organic matter covering is recommended to be between two and four inches in thickness.

Add Coffee Grounds to the Potting Mix When Repotting

Mint is a fan of loose, well-drained mineral soils that have a amount of organic matter. This is why it is possible to work grounds of coffee directly into the soil while planting. This is also true for transplanting.

The great thing about grounds of coffee are that they slowly release nutrients. This means that you can count on your mint plants to receive an infrequent dose of nitrogen as well as other nutrients. In the mix for potting, they will provide your mint plants with food over the course of six to eight months.

But, you should apply the coffee grounds using an effective, water-soluble (or liquid) fertilizer. This will supply nutrients to the plant while microbes work on grounds of coffee.

Coffee Grounds as Compost Tea

First, you must prepare the compost, or fertiliser tea from coffee grounds. Mix five gallons of drinking water (preferably distilled or filtering) with two cups spent coffee grounds.

The concoction should be allowed to sit and blend for at least a night or for at least a few hours. Then, you can use the compost tea as fertilizer for your pots and garden mints.

It is also possible to use coffee ground tea as an easy foliar feed. All you need do is apply the mixture onto the leaves. The mint will be smiling with its bright green leaves.

Water after Application

Its a good idea to moisten your mint immediately after applying the coffee grounds directly to the soil. It will accomplish three things:

  1. The plant could be thirsty
  2. Water can help push organic particles from the coffee grounds down to the mix of potting, and
  3. Water can help to eliminate some caffeine that could harm the plant.

It is ideal to water your mints early in the early morning. This will let it absorb the right amount of moisture and nutrients prior to the suns heat onset.

Use Drip Feeding Method

You can employ the drip-feeding method once youve crafted the compost tea.

- Using Water Bottle for Drip Feeding

Youll require tape two pieces of wood as well as a sturdy water bottle.

  • Use wood and tape to secure your bottle upright
  • Make a lip using the bottom end of the bottle.
  • Make a drip hole in the lid that is on the top of the bottle.
  • Drink one cup of compost tea from the lower part of the container.

Let the tea run off from the bottle onto your mint. It will take anywhere from 1 to 2 days for the tea to get rid of the excess.

- Using Rope for Drip Feeding

Youll require a fine cotton wicking rope as well as an empty bucket.

  • Lift the bucket up and add compost tea to it.
  • Make sure that one end of the rope is inside the bucket, and the other is just a little bit buried into the mints soil.
  • It will move through the container to your mint through capillary action.

Don’t Use Coffee Grounds on Seedlings

It is possible to stay clear of coffee grounds for mint seedlings. The acidic nature and the presence of caffeine can hinder development and germination of your seedlings or seeds.

Additionally, coffee grounds are a source of organic particles that can create a cement-like coating which doesnt permit water or air to move.

Benefits of Using Coffee Grounds

Deter Pests

The coffee grounds for a number of years been used for a variety of reasons to keep insects out of plants. This is particularly applicable to snails, slugs, and other insects that could be a nuisance to your mint in pots or in your garden. What is the reason?

One theory suggests that caffeine as well as other substances in coffee negatively affect these insects. Its important to remember that theyre also rough. They tend to avoid the soil that has coffee grounds.

The coffee grounds can also serve as a binding agent to the majority of organic and chemical pesticides. This can help kill and keep out the spread of pests over a longer period.

Prevent Diseases

Like insects, disease is often attracted by mints that have been either weak or stressed. Coffee grounds fight off disease in many ways.

Its an excellent source of nutrients which keep your mints in good health. In addition, it helps fight against pests that could cause illness or damage to the plant.

The colonies of fungal and mold in coffee grounds that are decomposing help to stop the development of pathogenic bacteria as well as species of fungi. They are pathogens responsible for the wilts and rots like Sclerotinia, Pythium, and Fusarium.

Improves Soil Quality

Coffee grounds are a great soil conditioner. The organic matter that is found in them does more than enhance soil structure. It also improves the flow of water particularly when it is combined with organic substances.

Additionally the coffee grounds are high in nutrients that can boost the potting mix of your plants and compost. Some studies have revealed that the nitrogen content (by volume) is around 2percent, but other studies claim it could be up to 10 percent. (Source: Oregon State University)

In any case nitrogen is vital to the growth of foliage. Coffee grounds can increase the levels of copper, magnesium and potassium, as well as phosphorus, potassium and iron.

Water Retention Capacity

Because they are organic, the coffee ground increase the capacity to retain water in the soil in a dramatic way. If you apply more than five percent of the area of soil, the grounds could cause a barrier to the aeration process and also to moisture.

Improves Drainage Capacity

Like most potted plants, mints hate poor drainage and soggy soil. They require soil that is loose to allow the roots to be easily absorbed. Coffee grounds are fortunately, as they contain lots of organic matter which improves drainage capacity.

This can keep water from getting into the soil. This will aid in preventing the roots of your plant from becoming soaked and becoming rotten.

Keeps Pets Away

Although its controversial, many people apply coffee grounds to the soil for potting to deter pets particularly cats. They dont like the taste or scent of coffee, so its a great repellent for cats.

Increases Soil Acidity

Mint thrives in an acidic pH ranges between 5.5 to 6.5 (others suggest 6.5-7.0). Coffee grounds can cause acidity in the soil you plant in. Make sure you test the pH level of your soil before you do so.

Problems with using Coffee Grounds on Mint

Promotes Fungal Growth

As weve already mentioned that coffee grounds are made up of organic matter that holds moisture. In reality, a thick layer of grounds will expand and form a moist silo which encourages the development of anaerobic fungal.

Due to the moisture and acidity as well as the high nitrogen levels, you could be able to spot mildew, mold, as well as various fungal growths. Include organic material to prevent this.

Excess Moisture Retention

Coffee grounds contain fine organic particles, such as clay. If used as mulch, they can swell and create a barrier that holds moisture in the soil. It also blocks water and air from entering.

Attract Pests

Coffee grounds can deter insects, including snails and snails. However, it can provide ideal conditions to draw other insects.

This proves that it is best to compost with grounds from coffee rather than using them to fertilize your mint.

Can Inhibit Growth of Mint

In the event that your mix already contains enough nitrogen, then adding coffee grounds can stifle the mint. Additionally, the caffeine in the soil is absorbed by water.

Once it is in the system the compound will stop the development of your mint, particularly seedlings and plants that are young.

Potential Risks to Soil

Your mint likes mildly acidic soil. However coffee grounds are extremely acidifying. Therefore, if your soil is already acidic enough and acidic, then adding coffee grounds might not be the best idea.

Drinking water by combining Leftover Coffee?

I dont like pouring cold coffee that is stale into the garbage. If you dont like to throw away your coffee your coffee, then youre probably wondering if you can water your mint using leftover coffee.

Youre right in the right direction. The mint you have is a little acidic soil. Therefore, watering it leftover coffee can work well for it.

Final Thoughts

  • Coffee grounds are great for mints - it improves soil quality, neutralizes the soil, and increases drainage capacity.
  • It is best to compost coffee grounds instead of using directly to fertilizer.
  • Do not use coffee grounds in seedbeds or seedlings. They will impede their growth.


Went from an inexperienced gardener to a half-decent one over 10+ years. I cover anything from general indoor plant guides and lawn care, to succulents and flowers. Super happy to share my tips and tricks with you :)