How to use coffee grounds as fertilizer
A Common-Sense Guide to Using Coffee Grounds in the Garden
, written by Ann Marie Hendry
Coffee shops often give coffee grounds away free to gardeners, as they’re a waste product they would normally have to pay to dispose of. For coffee-loving gardeners like me, this freely available resource sounds like a real boon. But some gardeners suggest that using coffee grounds could be ineffective or, worse, harmful to plants.
I decided to sort the facts from the hype and find out just how beneficial – or otherwise – coffee grounds are in the garden.
Using Coffee Grounds as Mulch
Mulching is incredibly beneficial but it’s notoriously difficult to come by compost, straw or other organic matter in large enough quantities at a low enough price. Using free coffee grounds seems like the perfect solution, but some gardeners have found that using coffee grounds directly on the soil has had a disastrous effect on plants. However this seems to be linked to using thick blankets of it to mulch around plants and over seeds.
The reason for this could be that coffee beans contain caffeine, which is said to suppress the growth of other plants to reduce competition for space, nutrients, water and sunlight. How much caffeine actually remains in used coffee grounds is debatable, and some plants will be more sensitive to caffeine than others. It would be sensible to avoid spreading coffee grounds around seeds or seedlings as they may inhibit germination and growth.
There is a more obvious reason why using coffee grounds alone for mulching could be detrimental. Like clay soil, coffee grounds consist of very fine particles that are prone to locking together. This turns them into a barrier that will resist water penetration and eventually result in plants dying of thirst.
The solution is to mix coffee grounds with other organic matter such as compost or leafmold before using it as a mulch.
Alternatively, rake your coffee grounds into the top layer of soil so that they can’t clump together. Variable particle sizes is key to good soil structure.
Coffee grounds are often said to be acidic but this can vary a lot, from very acidic to slightly alkaline, so don’t expect them to acidify higher pH soils.
Sprinkle used coffee grounds around plants as a slow-release fertiliserUsing Coffee Grounds as Fertilizer
Many of us will have dumped the cold remains of a forgotten coffee in a plant pot at some point, and then perhaps wondered if it was the wrong thing to do! But it turns out that coffee grounds contain a good amount of the essential nutrient nitrogen as well as some potassium and phosphorus, plus other micronutrients. The quantity and proportions of these nutrients varies, but coffee grounds can be used as a slow-release fertilizer.
To use coffee grounds as a fertilizer sprinkle them thinly onto your soil, or add them to your compost heap. Despite their color, for the purposes of composting they’re a ‘green’, or nitrogen-rich organic material.
Make sure to balance them with enough ‘browns’ – carbon-rich materials such as dried leaves, woody prunings or newspaper. Your compost heap’s tiny munchers and gnawers will process and mix them effectively, so using coffee grounds in this way is widely accepted to be safe and beneficial.
Many vermicomposters say that their worms love coffee grounds, so small quantities could also regularly be added to a worm bin if you have one. Paper coffee filters can go in too.
Used coffee grounds can safely be added to the compost heapCoffee Grounds as a Natural Pesticide
An oft-repeated nugget of advice is to spread used coffee grounds around plants that are vulnerable to slug damage. There are two theories why: either the texture of the grounds is abrasive, and soft-bodied slugs prefer not to cross them, or the caffeine is harmful to slugs so they tend to avoid it.
However in an experiment slugs took just seconds to decide to cross a barrier of coffee grounds! The same researcher also sought to find out if coffee grounds would repel ants, with similar results – ants may not particularly like coffee grounds, but they won’t scarper out of your garden to get away from them.
Coffee Grounds and Dogs
One word of warning though: coffee grounds may not have much effect on pests, but they can be harmful to pets in large enough doses. It’s hard to say what would be a large enough dose to cause poisoning because the amount of caffeine in used coffee grounds varies. But if you have a dog that insists on sampling anything that smells halfway agreeable, it would be wise to avoid laying coffee grounds directly onto the garden. Bury them in your compost heap instead.
Coffee grounds are free organic matter, whether a by-product of your at-home daily brew or collected from coffee shops that are only too glad to give them away for nothing. If used with care and common sense, they are a worthwhile addition your compost heap and your soil.
Have you used coffee grounds in the garden? What was your experience? Share it with us by leaving a comment below!
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How to Use Coffee Grounds in Your Garden
If you make a daily pot of coffee, you have a fabulous source of organic matter right at your fingertips. Coffee grounds can make your garden happier in several ways, and not just that coffee gives you more energy for weeding and pruning. Don't toss the grounds! You can put them to work.
Put coffee grounds in your compost bin. There are two types of compost material: brown and green. Your coffee grounds may be brown in color, but in compost jargon they are green material, meaning an item that is rich in nitrogen. Coffee grounds are approximately 1.45 percent nitrogen.
They also contain magnesium, calcium, potassium, and other trace minerals. Other green compost materials include food scraps and grass clippings.
Adding coffee grounds and used paper coffee filters to your compost will provide green compost material. However, it must be balanced with brown compost material, which includes dry leaves and newspapers. There should be a 4-to-1 ratio of brown compost material to green compost material. If you have too much green material your compost pile will start to smell. If you don't have enough, the compost pile won't heat up.
The Spruce / Sarah CrowleyFertilize With Coffee Grounds
Add coffee grounds directly to the soil in your garden. You can scratch it into the top couple inches of soil, or just sprinkle the grounds on top and leave it alone. In smaller amounts, especially when mixed with dry materials, coffee grounds will give up their nitrogen. Used coffee grounds are actually nearly neutral in pH, so they shouldn't cause concerns about their acidity.
Be careful not to use too many coffee grounds or pile them up. The small particles can lock together, creating a water resistant barrier in your garden.
You can also make coffee ground "tea." Add 2 cups of used coffee grounds to a 5-gallon bucket of water. Let the "tea" steep for a few hours or overnight. You can use this concoction as a liquid fertilizer for garden and container plants. It also makes a great foliar feed you can spray directly on the leaves and stems of your plants.
The Spruce / Sarah CrowleyFeed Your Worms
Add coffee grounds to your worm bin every week or so. Worms love coffee grounds! Just don't add too many at once, because the acidity could bother your worms. A cup or so of grounds per week for a small worm bin is perfect. In addition to using coffee grounds in your worm bin, earthworms in your soil will also be more attracted to your garden when you use them mixed with the soil as fertilizer.
Keep the Pests Away
Create a slug and snail barrier.
Coffee grounds are abrasive, so a barrier of grounds placed near slug-prone plants may just save them from these garden pests. However, be warned that some researchers quibble with this advice and don't think it is effective. You may want to have a backup plan in mind if it doesn't work. Many cats dislike the smell of coffee grounds and may avoid using your garden as a litter box if you mix coffee grounds into the soil.
Fresh Coffee Grounds for Acid-Loving Plants
While used coffee grounds are only slightly acidic, fresh (unbrewed) coffee grounds have more acid. Your acid-loving plants like hydrangeas, rhododendrons, azaleas, lily of the valley, blueberries, carrots, and radishes can get a boost from fresh grounds. However, tomatoes do not like fresh coffee grounds; keep them out of that area of the garden. This could be a good use for coffee that is getting old in your pantry or a type you bought for visiting friends but isn't your usual cup of joe.
Fresh coffee grounds still have most of their caffeine content as well as the acid. Don't use coffee grounds on seedlings or very young plants, as caffeine can stunt their growth. Be cautious in using fresh grounds around pets or your wire terrier may become extremely wired.
The Spruce / Sarah CrowleyDissenting Research Into Coffee Grounds in the Garden
One 2016 research study found that using spent coffee grounds in growing broccoli, leek, radish, viola, and sunflower resulted in poorer growth in all soil types, with or without additional fertilizer. The good news is that the coffee grounds improved the water holding capacity of the soil and decreased weed growth. The researchers think the poorer growth was due to the plant-toxic compounds naturally present in the coffee grounds. If you aren't getting the results you hoped for with coffee grounds, you may want to try your own experiments with and without them in your garden.
90,000 for which plants are suitable, how to use cake and ground coffee in the garden and gardenContent:
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- For which plants are
- Methods of use
- Watering
- Mulching
- Supplement
- compost
- for soil seedlings
- Pest protection
- Where not to use
- Helpful tips
thick as a fertilizer for indoor plants, flowers and gardens.
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.
- 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.
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. 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, 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.
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.
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 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.
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.
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.
the pros and cons of using coffee in the garden and in the garden - an article on TCHK
The advice not to throw away coffee grounds, but to take it under the tomato bush can be found in many collections of non-traditional uses of coffee. Compost, fertilizer, insecticide and soil acidifier - a variety of useful properties are attributed to this product.
In fact, everything is not as simple as it seems at first glance. Below, we will look at a few of the main arguments for using coffee in the garden and see which ones should be treated with caution.
Is coffee a useful fertilizer?
There is a common belief that coffee grounds can act as an ideal natural way to feed the beds: they contain about 3% of useful micronutrients, including magnesium, potassium, calcium and phosphorus, as well as nitrogen. However, "natural" does not mean "safe" and "useful".
According to a 2016 study by Australian scientists, recommendations for using used coffee grounds either directly in the soil or as compost should be considered... anecdotal. Empirically, the Australians have found that this kind of "fertilizer" not only does not improve growth rates, but even reduces them.
Why? Looks like it's all about the caffeine. There is a lot of it even in the sleeping coffee grounds. Now raise your hand if you remember that caffeine is toxic to other non-caffeine plants.
In addition, coffee grounds have antibacterial properties, which negatively affects the natural processes characteristic of composting.
However, one cannot fail to mention exceptions. According to the experience of experienced flower growers, azaleas, roses, hydrangeas and camellias respond well to such top dressing, increasing the number of buds. I like the coffee diet and evergreen shrubs, as well as ferns.
Coffee acidifies alkaline soil
One of the most common gardening tips about coffee grounds is to use them to acidify the soil. It seems to make sense: everyone knows that coffee is sour. The question is how sour the thick will be.
It turns out not very good.
Although the caffeine is still present in this product, the acid present in the grain is water soluble. Therefore, our drink becomes sour, and not the used grounds, which have a pH close to neutral (from 6.5 to 6.8 pH).
The conclusion is obvious. Coffee as an acidifier is pure myth.
The used grounds practically do not have the acidic properties of the drink.
Coffee keeps pests away
Really does. After all, caffeine is toxic not only to plants, but also to insects. Scientists have already proven that coffee grounds are very effective against bugs and midges. There is a version that it also helps to drive away slugs and snails, but this hypothesis requires additional research.
Coffee is an effective soil conditioner
On the one hand, yes, the coffee grounds add some looseness. However, at the same time, its toxic properties continue to work, which means that the active use of such an additive will destroy the gardener's main friends - worms. Many Internet sources write that worms like coffee, but in reality, such a feast will have an extremely negative impact on their health. Well, then it’s easy to calculate: no worms - no natural “baking powder”.
Coffee against weeds
As we remember, caffeine inhibits plant growth.
