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Is leftover coffee good for plants


How to Use Coffee to Water Plants

By

Colleen Vanderlinden

Colleen Vanderlinden

Colleen Vanderlinden is an organic gardening expert and author of the book "Edible Gardening for the Midwest." She has grown fruits and vegetables for over 12 years and professionally written for 15-plus years. To help move the organic gardening movement forward, she started an organic gardening website, "In the Garden Online," in 2003 and launched the Mouse & Trowel Awards in 2007 to recognize gardening bloggers.

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Updated on 06/07/22

Reviewed by

Mary Marlowe Leverette

Reviewed by Mary Marlowe Leverette

Mary been a Master Gardener for 30+ years and a commercial and residential gardener for 50+ years. She is a former Clemson University Extension Agent. She worked to develop the Riverbanks Botanical Garden that opened in 1995. Mary co-owns Marlowe Farms Apple Orchards.

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Fact checked by

Emily Estep

Fact checked by Emily Estep

Emily Estep is a plant biologist and fact-checker focused on environmental sciences. She received a Bachelor of Arts in Journalism and a Master of Science in Plant Biology from Ohio University. Emily has been a proofreader and editor at a variety of online media outlets over the past decade.

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The Spruce / Danielle Holstein 

Coffee is part of our daily life and a common gardening question is whether it's okay to water plants with leftover coffee or to add coffee grounds to the compost pile.

The answer is yes, in some situations using coffee when gardening is not only acceptable but a good idea. There are some caveats, though. 

Using Leftover Coffee Grounds

The Spruce / Danielle Holstein

Coffee grounds are a good source of nitrogen in your compost pile or when added directly to the soil in the garden. If added in fairly large amounts, they can raise the acidity level of the soil for acid-loving plants such as blueberries, azaleas, and rhododendrons. Coffee grounds sprinkled over the ground around acid-loving plants serve as a mild acid fertilizer for them. And worms seem to love them, either in your garden or outdoor compost pile or in a vermicompost bin.

And coffee grounds are regarded as an effective natural deterrent to garden pests such as slugs, snails, and ants. Rumors of coffee grounds repelling deer may be overstated. Deer are voracious eaters, and a few cups of coffee grounds are unlikely to make much of a difference. Coffee grounds will discourage a mischievous cat from roaming in your garden, but its effectiveness on rabbits and other common garden rodents is unknown.

Tip

If you're not a coffee drinker, don't forget your used tea leaves. They work great as a soil enhancer around acid-loving plants and add nutrients to compost piles.

How to Use Leftover Liquid Coffee

The Spruce / Danielle Holstein 

If you brew coffee by the pot, you may wonder if the cold leftovers can be used to water plants. Or, can the remaining half cup of cold coffee in your mug be poured into that potted pothos plant next to your desk?

The short answer is: maybe. It depends on the plant. Plants that prefer more acidic soil (such as African violets, Impatiens, Norfolk Island pines, Phalaenopsis orchids, and Dieffenbachia) seem to respond well to a weekly watering with coffee. Outdoors, acid-loving plants like azaleas, Rhododendron, Siberian iris, lupine, and any pine trees or shrubs will do fine if periodically watered with cold coffee. Liquid coffee can also be used to water a compost pile that has become too dry. 

If you decide to try watering houseplants with coffee, keep a close eye on your plant. If the foliage starts yellowing or the tips of the leaves start turning brown, it's a sign that the coffee is adding too much acidity to the soil. It's not a bad idea to dilute your coffee with water, especially if you prefer your daily cup of java on the strong side. In some offices, the only "watering" plants received is from emptying leftover coffee into the soil, and they often do quite well. 

One caveat: if you add cream, milk, or sugar to your coffee, don't pour it into your plants. Ditto for flavored coffees. The sugars and fats can not only harm your plants and invite pests but can eventually result in a stinky mess. A plant watered with sweetened or flavored coffee may soon be overrun by fungal gnats or odorous house ants.

Article Sources

The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. Grounds in the Garden. Texas A&M University AgriLife Extension.

  2. Acid Soil Problems. Louisiana State University Agricultural Center.

  3. Fungus Gnats Tiny Flies Around Your Houseplants. University of Wisconsin at Madison Department of Entomology.

Coffee Used On Plants - How To Water Plants With Coffee

Home › Gardening How To › Soil, Fixes & Fertilizers

Soil, Fixes & Fertilizers

By: Amy Grant

Image by byryo

Many of us start the day with some sort of coffee pick me up, whether it’s a plain cup of drip or a double macchiato. The question is, will watering plants with coffee give them that same “perk?”

Can You Water Plants with Coffee?

Coffee used as a fertilizer is not exactly a new idea. Many gardeners add coffee grounds to compost piles where it decomposes and mixes with other organic matter to create some fantastic, nourishing soil. Of course, this is done with grounds, not the actual cold cup of coffee sitting here at my desk. So, can you water your plants with coffee proper?

Coffee grounds are about 2 percent nitrogen by volume, nitrogen being an important component for growing plants. Composting grounds introduces microorganisms that break down and release the nitrogen as it raises the temperature of the pile and aids in killing weed seeds and pathogens. Very useful stuff!

Brewed coffee also contains measurable amounts of magnesium and potassium, which are building blocks for plant growth as well. Therefore, it seems a logical conclusion that watering plants with coffee might indeed be very beneficial.

Of course, you wouldn’t want to use the cup sitting in front of you. Most of us add a little cream, flavoring, and sugar (or sugar substitute) to our Joe. While real sugar would not pose a problem to the plants, milk or artificial creamer won’t do your plants any good. Who knows what effect any of the many artificial sweeteners on the market would have on plants? I’m thinking, not good. Be sure to dilute before watering plants with coffee and don’t add anything else to it.

How to Water Plants with Coffee

Now that we have ascertained that we should use diluted coffee for plant fertilizer, how do we do it?

Coffee has a pH of from 5. 2 to 6.9 depending on the variety and preparation. The lower the pH, the more acid; in other words, coffee is pretty acidic. Most plants grow best in slightly acid to neutral pH (5.8 to 7). Tap water is slightly alkaline with a pH greater than 7. Therefore, using diluted coffee for plants can increase the acidity of the soil. Traditional chemical fertilizers, the addition of sulfur, or allowing leaves to decompose on soil surfaces are methods to decrease soil pH levels. Now you have another option.

Allow your plain brewed coffee to cool and then dilute it with the same amount of cool water as coffee. Then simply water acid-loving plants such as:

Water with the diluted coffee just as you would with plain tap water. Don’t use this to water plants that do not like acidic soil.

Don’t water every time with the diluted coffee fertilizer. Plants will sicken or die if the soil becomes too acidic. Yellowing leaves may be a sign of too much acid in the soil, in which case, abandon the coffee irrigation and repot plants in containers.

Coffee works great on many types of flowering indoor plants but can be used outside as well. Diluted coffee adds just enough organic fertilizer to encourage bushier, healthier plants.

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Coffee as a fertilizer and 6 more uses of coffee grounds in the garden

Coffee invigorates not only people, but also plants! If you are an avid coffee lover, do not rush to throw away the sleeping grounds. Make it "work" for your crop with our tips.

Many of us cannot imagine our morning without a cup of aromatic strong coffee. This black drink has a truly "magical" effect on the body: thoughts become clearer, efficiency and mood increase. Did you know that coffee can affect plants in much the same way? Of course, with proper application!

1. Coffee as a fertilizer

Naturally, in terms of efficiency, coffee cannot be compared with any fast-acting fertilizer, and even more so it cannot replace complex top dressing. But it is worth recognizing that the introduction of dormant coffee grounds into the soil around the plants has a beneficial effect on them.

Decaying organic matter increases the biological activity of the soil. First, it saturates the soil with nitrogen. Secondly, it attracts earthworms, which loosen the soil. Thirdly, coffee, used as a fertilizer, allows plants to more easily absorb copper, magnesium, potassium and phosphorus from the soil.

Even though coffee contains 2% nitrogen, this does not mean that it can replace a complete nitrogen fertilizer. Since coffee grounds take a long time to decompose, the elements are released slowly.

There is an opinion that coffee significantly increases the acidity of the soil, therefore it is suitable as a fertilizer only for plants that require a lower pH level (conifers, rhododendrons, heathers, etc.). However, this is not quite true. Coffee is really "sour", but only fresh.

Sleeping coffee grounds have a neutral reaction - about pH 6.5-6.8 (with an ideal acid-base balance of pH 7). For fidelity, it is advisable to rinse the thick with clean water before using it in the garden.

2. Coffee grounds compost

Composting used coffee is as simple as throwing the grounds into the compost heap. Again, given the controversy about its acidity, for greater peace of mind, it is advisable to pre-rinse it under running water.

Paper coffee filters can also be sent along with the grounds. All this will pereprete and will benefit the plants.

The only important thing to consider when composting is the correct selection of compost components. In addition to coffee grounds and other food waste, more "solid" components should be added to the compost pit: straw, wood residues, manure, grass clippings, etc. Coffee grounds should be no more than 15-20% of the total compost, otherwise it simply will not rot.

3. Coffee grounds mulch

Many gardeners use coffee grounds as an environmentally friendly mulch. It is safe for plants, releases nutrients into the soil, enriches it with nitrogen, attracts earthworms, looks natural and is pleasing to the eye.

However, the main disadvantage of such mulch is that it can start to mold. To prevent this from happening, again, we advise you to rinse the thick with clean water and dry before spreading over the soil surface.


In addition, if you drink coffee with sugar and milk, naturally, they remain on the coffee grounds. Sweet mulch can attract ants and other insects. Therefore, it is necessary to wash the mass before drying.

4. Soil improver

If the quality of the soil in your area leaves much to be desired (it is too light, or, on the contrary, not enough air and moisture permeable), its structure must be improved. Good soil "breathes", easily passes air and moisture. To achieve this effect, you can add coffee grounds to the top layer of soil.

5. Growing herbs in coffee

As an interesting experiment, you can try growing herbs in a container filled with coffee substrate. Such a project called Urb was proposed by London-based industrial designer Blake Parkinson.

The main thing is to periodically feed seedlings with complex fertilizers in order to prevent nutrient deficiencies.

6. Pest barrier

It is believed that coffee grounds scattered around plants provide a reliable barrier against slugs and snails, which are a real scourge of some crops.

In addition, according to some gardeners, coffee can not only scare away, but also destroy the larvae of insect pests, including mosquitoes and bedbugs.

Of course, in the fight against insects dangerous for the crop, you should not rely solely on coffee, but it will not hurt to bring it to your side as an additional ally.

7. Cat Repeller

If you are outraged by the fact that cats use your beds as a toilet, generously "sprinkle" the garden with coffee grounds. The strong coffee smell will discourage the tailed pranksters from any desire to relieve themselves in this place.

Do you use spent coffee grounds in your garden? Share your experience on our forum.

90,000 for which plants are suitable, how to use cake and ground coffee in the garden and garden

Content:

    1. For which plants are
    2. Methods of use
      • Watering
      • Culting
      • Complex
      • compost
      • For seedlings
      • Pest protection
    3. Where Not to Use
    4. Helpful Hints

Many people start their day with a cup of freshly brewed coffee, and after this daily ritual there is always a pulp that can simply be thrown into the bin or coffee grounds can be used as fertilizer for indoor plants , flowers and garden.

The answer to the question of whether coffee grounds can be used as fertilizer is obvious: of course you can! But let's take a closer look at what benefits this brings to plants.

  1. By adding coffee grounds to the soil, especially clay and loam soil, its structure becomes looser, drainage capacity and air exchange improve. In addition, coffee attracts earthworms, which also contribute to loosening the soil.
  2. The smell of coffee can repel harmful insects. He doesn't like cats either. If you sprinkle your garden beds with coffee grounds, you don't have to worry that uninvited visits from your pet will damage tender plantings.
  3. It is believed that fresh coffee has an increased level of acidity, and top dressing with such characteristics is not suitable for every plant. However, to avoid acidification of the soil, it is enough to shed thick water and then apply in the garden or vegetable garden.
  4. Coffee grounds as a fertilizer are rich in minerals and trace elements. Potassium and phosphorus contribute to good flowering and abundant fruiting. Nitrogen activates the rapid growth of plants. Copper helps to resist a number of diseases. And although the total amount of useful substances in coffee cake is about 2–3%, which means that it can hardly be considered a full-fledged fertilizer, the use of grounds as an organic plant food is fully justified.

What kind of plants is the coffee fertilizer suitable for

And yet, dormant coffee is a nutrient that is not suitable for every plant. Therefore, before you widely use it in your garden, you need to study for which plants it is most effective to use coffee grounds as a fertilizer. It is most useful for flowers that prefer a low pH level - azaleas, hydrangeas, heathers and rhododendrons. Due to the large amount of potassium in the composition, coffee grounds can be used as a fertilizer when growing vegetable crops such as tomatoes, potatoes, cucumbers, and peppers. Feeding fruit trees with sleeping coffee will also help to significantly increase their fruiting. Magnesium, which is part of coffee, is useful for berry bushes. Magnesium and potassium will help to get a high yield of root crops, while nitrogen is indispensable for green crops.

Roses, palms, ficuses and ferns, as well as violets and asparagus, respond best to coffee fertilization. When using coffee grounds as a fertilizer for houseplants, it is recommended to shed and dry it first. If you simply pour the rest of the coffee from the cup into the pot, most likely there will be no benefit, but on the contrary, the soil may become covered with a crust and begin to mold. To prevent this, you need to mix the prepared thick with soil suitable for this type of plant.

Coffee with sugar or milk should not be used for horticultural, horticultural and flower crops, since sugar attracts ants, and milk provokes the development of putrefactive processes in the soil, which can damage the root system of plants.

Methods of use

Watering

Used coffee must be diluted with a sufficient amount of liquid before it can be used as a fertilizer for watering plants. To prepare a solution for 10 liters of water, 1 cup of grounds is required. Cake is poured with a small amount of water and left to swell for about a day. After swelling, the amount of liquid is adjusted to the calculated amount and used for watering plants.

After feeding the plants with coffee grounds, it is advisable to water the soil again, but with clean water. This technique will allow the minerals to be slowly released, nourishing the plants. When planting bushes, you should spill the ground with coffee solution at the rate of 1 liter under the bush.

Mulching

Coffee grounds can also be used for mulching plantings to protect the soil from drying out, repel pests and improve soil structure. However, it must be remembered that when using the grounds as mulch, as in the case of using coffee cake as a fertilizer in the garden in the country, it should be thoroughly dried to prevent the development of mold.

Soil supplement

Dormant ground coffee as a fertilizer can be added to the planting hole or hole before planting to improve soil structure. This technique makes the land more drained and loose, which ultimately has a positive effect on plant health and yield. When used on light soils, the thick acts as a binder. In this case, top dressing is applied to the upper soil layer at the rate of 200 ml per 1 m².

Compost

To speed up the maturation of the compost, it is enough to spill each layer no more than 10 cm thick with coffee infusion. Coffee grounds perform the function of nitrogen components that trigger an exothermic reaction inside the compost heap, in other words, heating it up, due to which the compost matures much faster. This method is so effective that some summer residents specifically purchase inexpensive varieties of ground coffee and sprinkle layers of compost on them.

For seedlings

Recently, the method of growing vegetable seedlings on a coffee substrate has become popular. But in order to prevent depletion of the soil, it is necessary from time to time to feed the seedlings with complex fertilizers.

Protection against pests

Coffee pomace as a fertilizer in the garden is also very effective for protecting plants from mature individuals of harmful insects - ants, snails, aphids, slugs. According to the experience of some gardeners, coffee can also destroy pest larvae, in particular mosquitoes and garden bugs. This remedy is not as effective as insecticides, but also much safer.

Where not to use coffee grounds

Coffee grounds are rich in nitrogen, so if used in excess, you can burn the root system, which will lead to the death of the plant.

Poorly dried coffee waste can cause mold and fungal diseases and kill plants. In addition, coffee fertilizer is not suitable for tradescantia, asparagus, geraniums and other crops that prefer more alkaline soil. Top dressing from pomace can change the shade of rose flowers.

Helpful Hints

Dried coffee grounds are very light, so when used dry, even the slightest breeze can blow them off the garden.

Learn more