Coffee Grounds in Compost
Composting with used coffee grounds 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 and is as easy as throwing the used coffee grounds onto your compost pile.
Used coffee filters can be composted as well. However, if you will be adding used coffee grounds to your compost pile, keep in mind they are considered green compost material and will need to be balanced with the addition of some brown compost material (organic matter).
Coffee Grounds as Fertilizer
Applications for using used coffee grounds for gardening does not end with compost. Many people choose to place coffee grounds straight onto soil and use them as an organic fertilizer and soil amendment. The thing to keep in mind here is that, 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 they add organic material to the soil, which improves drainage, water retention and aeration in the soil. Used coffee grounds will also help micro-organisms beneficial to plant growth thrive and will also 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. But, this is only true for unwashed coffee grounds. 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.
Other Uses for Coffee Grounds in the Garden
Coffee grounds can be used in your garden in other ways. Many gardeners like to use used coffee grounds as mulch for their plants. Other uses for coffee grounds include using them to keep slugs and snails away from plants.
The theory is that the caffeine in the coffee grounds negatively affects these pests 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 also use coffee grounds as worm food, too, if you do vermicomposting with a worm bin. Worms are fond of coffee grounds.
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.
Source: Gardening Know How
Chemical Composition of Coffee
DYK? Not everything contained in a coffee bean makes it into your morning coffee. Nitrogen-rich proteins needed for seed germination and growth comprise over 10% of coffee grounds. In fact, the carbon-to-nitrogen ratio of coffee grounds can be as low as 11:1, an ideal ratio for plant and soil nutrition.
Since coffee is extracted in water, most of the hydrophobic compounds, including oils, lipids, triglycerides, and fatty acids remain in the grounds, as do insoluble carbohydrates like cellulose and various indigestible sugars.
Structural lignin, protective phenolics, and the wonderful aroma-producing essential oils are also left over from the brewing process. It’s this last group of chemicals that are reported to have antioxidant and antimicrobial properties.
Source: Dr. Linda Chalker-Scott in The Master Gardener, WSU