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.
Using Coffee Grounds as 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.
To use coffee as a plant fertilizer, you'll need to dilute it. It should look like weak tea. If you aim for about 1/4 coffee and 3/4 water, or even a half-and-half mix, in your solution (depending on how strongly you brew your coffee), that's about right, but you don't have to be fussy about it.
She recommends that grounds make up no more than 15 to 20% of the total compost volume. Because they are acidic, coffee grounds make good acid mulch. Of course, too much of anything is just too much, so apply coffee grounds in limited amounts.
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.
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.
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.
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.
Plants that like coffee grounds also respond well to watering with coffee liquid. However, it is a fairly strong fertilizer, so this watering should not be done more than once a week.
Coffee grounds repel pests. Most pests do not like the smell of coffee, so they will stay away- Fungus Gnat is no different. If your coffee grounds are not repelling them, you're not doing it right. One thing you would have to do is to avoid spreading the coffee grounds on the face of your potting soil.
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 can be used when planting perennials, shrubs and bushes, or added to the soil around those growing throughout the year. Adding a few tablespoons when planting perennials helps add nutrients and soil structure for long-term growth.
Coffee grounds contain around 2% nitrogen as well as varying amounts of phosphorus and potassium which are all very important for the growth of tomato plants.
"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.
For successful production, a free draining soil with a minimum depth of one metre is required. Coffee will not tolerate waterlogging or 'wet feet'. Coffee can be grown on many different soil types, but the ideal is a fertile, volcanic red earth or a deep, sandy loam. Yellow-brown, high silt soils are less preferred.
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.
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.
'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.
Enter coffee grounds and eggshells. While we may consider them to be trash, they provide a healthy snack for plants, offering a one-two punch of nitrogen and calcium. According to Los Angeles-based collective LA Compost, these nutrients support healthy plant growth in almost any soil bed.
Just as the aroma and caffeine of a cup of Joe in the morning stimulates many of us, using coffee ground on grass can also stimulate healthier turf. It isn't the caffeine that stimulates healthy grass growth, but rather the nitrogen, phosphorus and trace minerals that coffee grounds contain.
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 beans, grounds and brewed coffee contain caffeine, a very dangerous and toxic chemical to cats and dogs. Ingestion can be life threatening. According to the Pet Poison Helpline, a moderate amount of coffee can easily cause death in small dogs or cats.