In terms of fertilizing soil, coffee grounds do have significant nitrogen content, which means they can help improve soil fertility. But because they also affect microorganisms in soil, plant growth and possibly soil pH, you don't want to rely on coffee grounds as plant food.
Coffee grounds can most certainly be added to your compost and also directly to your soil. Instead of simply tossing them out though, you may wish to incorporate them a bit more thoroughly by digging them in.
Lignin, phenolics, and essential oils are also left over from the brewing process and these compounds are reported to have antioxidant and antimicrobial properties. Soil-borne bacteria and fungi break down the various chemical components of coffee grounds after several months.
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.
Coffee grounds take three to four months or more to decompose, depending on the soil microbial activity and health. The more microbial activity of the soil, the more quickly coffee grounds decompose.
In most cases, the grounds are too acidic to be used directly on soil, even for acid-loving plants like blueberries, azaleas and hollies. Coffee grounds inhibit the growth of some plants, including geranium, asparagus fern, Chinese mustard and Italian ryegrass.
How Often Should You Add Coffee Grounds to Plants? You can fertilize houseplants an average of 7 to 10 days in a row, but no more, as there is a risk of over-acidification of the soil. A cup of ground coffee should be added to the compost once a week.
Since coffee grounds have such a pungent and intense smell, mosquitoes do not like to come near it. Mosquitoes are repulsed by all types of coffee, whether it is fresh, used, or burnt. The most effective way to use coffee grounds for mosquito control is by burning them, as it creates a stronger aroma.
“the smell of the coffee repels snails, slugs and ants. You may also have success using coffee grounds to repel mammals, including cats, rabbits and deer.”
Not only do they repel mosquitoes, but also other insects such as wasps and bees. Coffee grounds are the bee's knees when it comes to staying bug bite free. Most bugs have a very strong sense of smell. Coffee grounds are very potent and even more potent once they are burned.
Coffee's bitter compounds are responsible for its repelling effects. These compounds make the coffee unpalatable to rats and mice. They will avoid areas where there is the use of coffee grounds.
The strong smell of coffee can be enough to keep cats off of your garden. Simply take your fresh, wet coffee grounds and distribute them around your borders and plants where you want to discourage feline attention. What's more, the coffee grounds are entirely biodegradable so they will decompose and enrich your soil.
Roaches are repelled by ground coffee. In fact, putting some ground coffee down in the corners or windowsills of your kitchen can actually help keep them insects away.
Other Natural Repellents
Mothballs — place them around the perimeter, and their pungent smell will repel snakes. Vinegar — mix it with water and spray often. Caffeine — sprinkle coffee grounds or instant coffee granules. Spices — chili powder and cayenne pepper work the best.
To use coffee grounds as a fertilizer, sprinkle them thinly onto the soil or add them to your compost pile. Spreading coffee grounds throughout your garden will also attract insects, such as, worms. Worms provide tons of nutrients to help your garden grow and thrive.
Coffee grounds will keep squirrels away from your garden because they do not like the smell. Simply sprinkle some fresh grounds on the soil surrounding your plants every two weeks. You can also try spraying your plants with a hot pepper spray for the same effect.
Mosquitoes hate the smell of lavender, citronella, clove, peppermint, basil, cedarwood, eucalyptus, peppermint, lemongrass and rosemary. They also hate smells such as smoke, for further insight, see our exploration on, does smoke keep mosquitoes away?
A great home remedy for wasps, with little equipment required: Just put a little coffee powder in a fire-proof bowl and light it with matches or a lighter until it glows. The smoke that rises steadily may keep wasps away from you!
Don't Reuse Coffee Grounds. Overall, we don't normally recommend reusing coffee grounds to make another cup or pot of coffee as it dilutes the flavor and can make the coffee taste more bitter than what is intended.
Coffee grounds are rich in nutrients, especially nitrogen. They also have some amount of other nutrients like potassium and phosphorous. Overall, this means that adding coffee grounds to your garden can work fairly well as a fertiliser. Coffee should be spread in a thin layer, rather than being clumped in one place.
Worms love to eat coffee grounds, and that's great news for your garden. Add coffee grounds to your compost pile to help attract worms, which help speed up the process of turning food scraps into compost. You can also add coffee grounds directly to the soil, but you'll have to be careful not to overdo it.
"It's fine to use coffee as a fertilizer," our senior lab testing technician, Jonathan Chan, says. "However, you should be careful because coffee can raise the acidity of the soil. Caffeine also is known to have a negative effect on plant growth."