What does coffee grounds do for soil

Coffee grounds and composting | OSU Extension Service

Coffee grounds are a great addition to the garden and compost pile. Help to recycle this great organic resource and reduce the amount of organics going to the landfill!

Some information about coffee grounds

Coffee grounds are about 2% nitrogen by volume.
Grounds are not acidic; the acid in coffee is water-soluble so the acid is mostly in the coffee.
Coffee grounds are close to pH neutral (between 6.5 to 6.8 pH).
Coffee grounds improve soil tilth or structure.
Coffee grounds are an excellent nitrogen source for composting. They have a C/N ratio of 20-to-1. In informal trials with OSU/Lane County Extension Service, Compost Specialists recorded sustained temperatures of 140 to 160 degrees Fahrenheit for up to two weeks when coffee grounds were 25% of the material in the compost pile by volume.
Anecdotal evidence suggests coffee grounds repel slugs and snails in the garden.

How do I use coffee grounds?

Spread the coffee grounds directly on the soil. Cultivate into the soil. If left to dry out, they can repel water.
Spread on the soil and cover with leaves or compost or bark mulch.
Add to the compost pile by layering the ingredients using 1/3 leaves, 1/3 fresh grass clippings, and 1/3 coffee grounds.
Add coffee grounds as part of a static compost pile, being sure to always add an equivalent amount of a carbon source such as shredded paper or dry leaves. Mix together well.

Coffee grounds are not a nitrogen fertilizer. In a germination test at the GrassRoots Garden in Eugene, OR, coffee grounds were mixed with potting soil at a ratio of 25% by volume. Lettuce seeds showed poor rates of germination and stunted growth compared to lettuce seeds planted in potting mix without coffee grounds.

Add paper coffee filters to the compost pile as a carbon source. Tear them into small pieces to speed decomposition.

If you are incorporating coffee grounds directly into the soil, add a nitrogen fertilizer at the same time. Coffee grounds encourage the growth of microorganisms in the soil, which use nitrogen for their growth and reproduction. While the coffee grounds are being broken down by the microorganisms, the additional nitrogen in the fertilizer will provide a source of nutrients for your plants. Add paper coffee filters to the compost pile as a carbon source. Tear them into small pieces to speed decomposition. Coffee grounds do not “go bad." For future use, store in a 32-gallon trash container near the compost bin or pile.

General composting tips

Composting with worms
Can I put barbecue ash in my compost or worm bin?
Answers to 3 common compost problems

Want to learn more about this topic? Explore more resources from OSU Extension: Garden Soil and Compost

Compost with coffee grounds

Photo: Pete Petryszak

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Using Coffee Grounds As Fertilizer

Home › Composting › Compost Ingredients

Compost Ingredients

By: Heather Rhoades

Image by ThamKC

Whether you make your cup of coffee daily or you have noticed your local coffee house has started to put out bags of used coffee, you may be wondering about composting with coffee grounds. Are coffee grounds as fertilizer a good idea? How do coffee grounds used for gardens help or hurt? Keep reading to learn more about coffee grounds and gardening.

Composting Coffee Grounds

Composting with coffee is a great way to make use of something that would otherwise end up taking up space in a landfill. Composting coffee grounds helps to add nitrogen to your compost pile.

Composting coffee grounds is as easy as throwing the used coffee grounds onto your compost pile. Used coffee filters can be composted as well.

If you will be adding used coffee grounds to your compost pile, keep in mind that they are considered green compost material and will need to be balanced with the addition of some brown compost material.

Coffee Grounds as Fertilizer

Used coffee grounds for gardening does not end with compost. Many people choose to place coffee grounds straight onto the soil and use it as a fertilizer. The thing to keep in mind is while coffee grounds add nitrogen to your compost, they will not immediately add nitrogen to your soil.

The benefit of using coffee grounds as a fertilizer is that it adds organic material to the soil, which improves drainage, water retention, and aeration in the soil. The used coffee grounds will also help microorganisms beneficial to plant growth thrive as well as attract earthworms.

Many people feel that coffee grounds lower the pH (or raise the acid level) of soil, which is good for acid loving plants. This is only true for unwashed coffee grounds though. Fresh coffee grounds are acidic. Used coffee grounds are neutral. If you rinse your used coffee grounds, they will have a near neutral pH of 6.5 and will not affect the acid levels of the soil.

To use coffee grounds as fertilizer, work the coffee grounds into the soil around your plants. Leftover diluted coffee works well like this too.

Other Uses for Used Coffee Grounds in Gardens

Coffee grounds can also be used in your garden for other things.

Many gardeners like to use used coffee grounds as a mulch for their plants.
Other uses for coffee grounds include using it to keep slugs and snails away from plants. The theory is that the caffeine in the coffee grounds negatively affects these pests and so they avoid soil where the coffee grounds are found.
Some people also claim that coffee grounds on the soil is a cat repellent and will keep cats from using your flower and veggie beds as a litter box.
You can use coffee grounds as worm food too if you do vermicomposting with a worm bin. Worms are very fond of coffee grounds.

Using Fresh Coffee Grounds

We get lots of questions about using fresh coffee grounds in the garden. While it’s not always recommended, it shouldn’t be a problem in some situations.

For instance, you can sprinkle fresh coffee grounds around acid-loving plants like azaleas, hydrangeas, blueberries, and lilies. Many vegetables like slightly acidic soil, but tomatoes typically don’t respond well to the addition of coffee grounds. Root crops, like radishes and carrots, on the other hand, respond favorably — especially when mixed with the soil at planting time.
The use of fresh coffee grounds are thought to suppress weeds too, having some allelopathic properties, of which adversely affects tomato plants. Another reason why it should be used with care. That being said, some fungal pathogens may be suppressed as well.
Sprinkling dry, fresh grounds around plants (and on top of soil) helps deter some pests same as with used coffee grounds. While it doesn’t fully eliminate them, it does seem to help with keeping cats, rabbits, and slugs at bay, minimizing their damage in the garden. As previously mentioned, this is thought to be due to the caffeine content.
In lieu of the caffeine found in fresh, unbrewed coffee grounds, which can have an adverse effect on plants, you may want to used decaffeinated coffee or only apply fresh grounds minimally to avoid any issues.

Coffee grounds and gardening go together naturally. Whether you are composting with coffee grounds or using used coffee grounds around the yard, you will find that coffee can give your garden as much of a pick me up as it does for you.

This article was last updated on 01/27/22

Content:

1. For which plants are
2. Methods of use
  - Watering
  - Mulching
  - Supplement
  - compost
  - for soil seedlings
  - Protection against pests
3. Where not to use
4. Helpful tips

thick as a fertilizer for indoor plants, flowers and gardens. nine0033

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.

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.
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. nine0008
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.
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. nine0008

What kind of plants is coffee fertilizer suitable for? 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. nine0033

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. nine0033

Coffee with sugar or milk should not be used for horticultural, horticultural and flower crops, as sugar attracts ants, and milk provokes the development of putrefactive processes in the soil, which can harm 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. nine0033

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 crops to protect 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. nine0033

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. nine0033

Protection against pests

Coffee pomace as a fertilizer in the garden is also very effective for protecting plants from sexually 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. nine0033

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. To prevent this from happening, it is recommended to mix the cake with earth or sawdust and close it shallowly into the soil. nine0033

If the color of the leaves of the plants has changed after treatment with coffee grounds, the use of coffee grounds as a fertilizer should be discontinued. You can carefully strain the coffee infusion and use only liquid for irrigation, and use the thick, for example, to feed conifers.

It is recommended to prepare fertilizer from coffee grounds for summer cottages, using cake from the preparation of only natural coffee. Instant powder and granulated coffee is not advisable to use for this purpose, since their nutritional value is not great. nine0033

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! nine0033

1. Coffee as a fertilizer

Naturally, in terms of effectiveness, 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. nine0033

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. nine0033

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 easy 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. nine0033

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. nine0033

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, conversely, 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. nine0033

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, serve as a reliable barrier against slugs and snails, which are a real scourge of some crops. nine0033

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 to 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.