Coffee grounds (and brewed coffee) are a source of nitrogen for plants, producing healthy green growth and strong stems. Coffee also contains calcium and magnesium — both of which are beneficial to plant health. To use coffee as a plant fertilizer, you'll need to dilute it. It should look like weak tea.
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.
'Coffee grounds are an excellent houseplant fertilizer due to their high nitrogen content (about 2 per cent) that releases slowly into the potting media as they decompose. However, coffee grounds have more to offer to plants than just nitrogen,' she says.
Yes, it's possible, but it should not be more than a thin sprinkling. If you add too much, the coffee grounds will form a dense layer on the surface of the potting soil that is impenetrable to water. On a regular basis, using leftover coffee to water your potted plants is a much better idea.
Coffee grounds are highly acidic, they note, so they should be reserved for acid-loving plants like azaleas and blueberries. And if your soil is already high in nitrogen, the extra boost from coffee grounds could stunt the growth of fruits and flowers.
Compost coffee grounds for a vegetable garden instead of using them directly. Remember, coffee grounds are not good for tomatoes or seedlings. Get a soil test, especially if your plants are not thriving or you want to change the acidity of the soil.
You know that last bit of coffee that always seems to be left in the carafe? Don't just pour it down the drain — you can use it to fertilize your plants, both indoor and outdoor. Coffee grounds (and brewed coffee) are a source of nitrogen for plants, producing healthy green growth and strong stems.
Composting used coffee
Ensuring a balanced mix of 'wet' and 'dry' materials is the best way to achieve good compost. The nutrients contained in coffee grounds will be recycled back onto the soil when finished compost is used as a mulch or dug into the soil. Also add any un-drunk coffee to dry material in a compost bin.
"The best way to use coffee grounds in plants is adding them to your compost pile, and then mixing a little bit of that compost in with your potting soil," Marino says. Diluting coffee grounds works the same way as diluting fertilizer: using just a teaspoon of coffee grounds per gallon of water.
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.
Like any type of fertilizer, coffee grounds are only effective when used sparingly. It is never a good idea to add too much, as that could do more harm than good. The proper proportion is usually around 4 to 1, or twenty-five percent of coffee grounds to mineral soils by volume.
You may love your morning coffee, but ants could do without it. Another natural way to deter ants, sprinkle coffee grounds outside and around your garden. The smell repels them and they'll be looking for a less caffeinated place to hang out. Want to keep your home clean and clear of ants?
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.
There are a select few plants that can benefit from fresh grounds—including acidity-loving Hydrangeas, Rhododendrons, Azaleas, Lily of the Valley, blueberries, carrots, and radishes—but generally, most common houseplants will prefer low to no acidity.
Coffee Grounds to Deter Pests
Coffee grounds are commonly used to keep animals including slugs, snails, rabbits and fire ants from eating plants in the garden, and to keep cats from treating garden beds like litter boxes.
The shells also contain other minerals that help plants grow, including potassium, phosphorus, and magnesium. Eggshells are, therefore, an effective and inexpensive fertilizer for outdoor garden soil and houseplants.
Eggshell Benefits
As it happens, eggshells can provide all the calcium carbonate the soil needs, which helps to lower the soil's pH level and make it more alkaline as opposed to acidic. This is incredibly beneficial for plant growth because many plants prefer to grow in soil that has low acidity.
The absorption of these nutrients encourages more rapid growth in the plant. Therefore, pouring soda on plants, such as Classic Coca Cola, is inadvisable. Coke has a jaw dropping 3.38 grams of sugar per ounce, which would certainly kill the plant, as it would be unable to absorb water or nutrients.
The best way to optimize your coffee grounds is to compost them using a simple 3:1 “browns” to “greens” method. Another option is to mix your coffee grounds into a homemade potting soil. Additionally, you can create a simple liquid fertilizer from leftover coffee.
The organic contents of cinnamon are perfect for increasing the root growth of plants. This spice's auxin content works to help the stem cuttings or seedlings sustain growth, all while protecting the plant with its antimicrobial and anti-bacterial qualities.
While many budding gardeners may be concerned that coffee grounds can attract pests, the reality is quite to the contrary. In fact, when implemented correctly, coffee grounds can be an effective way to repel certain pests such as wasps, snails, and mosquitoes.
Sarah says the key is composting them first. "Give it six months to a year. The compost will break down the phytotoxins, and you'll still get the great benefit to the soil from using them."
Recycling coffee grounds in your garden, or even a compost pile, rather than in a landfill is an excellent alternative to throwing them away.